I just want to report that when I flash the firmware again on both boards, everything seems normal now. I will update here again if I see anything out of order.

Just in case you need my M122:

m122
=== Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.4.0rc2 (2022-02-22 17:04:17) running on Duet 3 MB6HC v1.01 or later (standalone mode)
Board ID: 08DJM-956BA-NA3TJ-6JTDD-3SD6L-KA9UT
Used output buffers: 1 of 40 (26 max)
=== RTOS ===
Static ram: 150984
Dynamic ram: 96080 of which 140 recycled
Never used RAM 100468, free system stack 129 words
Tasks: NETWORK(ready,23.9%,207) ETHERNET(notifyWait,0.2%,168) HEAT(notifyWait,0.0%,321) Move(notifyWait,0.0%,269) CanReceiv(notifyWait,0.0%,793) CanSender(notifyWait,0.0%,356) CanClock(delaying,0.0%,339) TMC(notifyWait,9.7%,58) MAIN(running,66.1%,925) IDLE(ready,0.0%,30), total 100.0%
Owned mutexes:
=== Platform ===
Last reset 00:03:14 ago, cause: software
Last software reset at 2022-03-10 10:17, reason: User, GCodes spinning, available RAM 103468, slot 2
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00400000 BFAR 0x00000000 SP 0x00000000 Task MAIN Freestk 0 n/a
Error status: 0x00
Step timer max interval 138
MCU temperature: min 47.7, current 48.5, max 48.5
Supply voltage: min 24.0, current 24.1, max 24.1, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.0, current 12.1, max 12.1, under voltage events: 0
Heap OK, handles allocated/used 99/1, heap memory allocated/used/recyclable 2048/700/690, gc cycles 0
Events: 0 queued, 0 completed
Driver 0: pos 384000, standstill, SG min 0, mspos 74, reads 40263, writes 15 timeouts 0
Driver 1: pos 0, standstill, SG min 0, mspos 808, reads 40263, writes 15 timeouts 0
Driver 2: pos 64000, standstill, SG min 0, mspos 568, reads 40263, writes 15 timeouts 0
Driver 3: pos 0, standstill, SG min 0, mspos 401, reads 40264, writes 15 timeouts 0
Driver 4: pos 0, standstill, SG min 0, mspos 618, reads 40276, writes 3 timeouts 0
Driver 5: pos 0, standstill, SG min 0, mspos 947, reads 40275, writes 3 timeouts 0
Date/time: 2022-03-10 10:20:51
Slowest loop: 11.28ms; fastest: 0.05ms
=== Storage ===
Free file entries: 10
SD card 0 detected, interface speed: 25.0MBytes/sec
SD card longest read time 2.1ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, segments created 6, maxWait 81202ms, bed compensation in use: none, comp offset 0.000
=== MainDDARing ===
Scheduled moves 91, completed 91, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== AuxDDARing ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters 0 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamber heaters -1 -1 -1 -1, ordering errs 0
=== GCodes ===
Segments left: 0
Movement lock held by null
HTTP is idle in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty
=== CAN ===
Messages queued 1227, received 3694, lost 0, boc 0
Longest wait 2ms for reply type 6013, peak Tx sync delay 18, free buffers 50 (min 49), ts 635/635/0
Tx timeouts 0,0,0,0,0,0
=== Network ===
Slowest loop: 24.33ms; fastest: 0.02ms
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0), 0 sessions Telnet(0), 0 sessions
HTTP sessions: 1 of 8
- Ethernet -
State: active
Error counts: 0 0 0 0 0
Socket states: 5 2 2 2 2 2 0 0

M122 B121

m122 b121
Diagnostics for board 121:
Duet TOOL1LC rev 1.1 or later firmware version 3.4.0rc2 (2022-02-22 10:15:02)
Bootloader ID: SAMC21 bootloader version 2.3 (2021-01-26b1)
All averaging filters OK
Never used RAM 2624, free system stack 62 words
Tasks: Move(notifyWait,0.0%,153) HEAT(notifyWait,0.2%,115) CanAsync(notifyWait,0.0%,59) CanRecv(notifyWait,0.0%,76) CanClock(notifyWait,0.0%,65) ACCEL(notifyWait,0.0%,61) TMC(notifyWait,3.0%,57) MAIN(running,91.9%,335) IDLE(ready,0.0%,26) AIN(delaying,4.9%,142), total 100.0%
Last reset 00:03:48 ago, cause: software
Last software reset data not available
Driver 0: pos 0, 800.0 steps/mm,standstill, SG min 6, read errors 0, write errors 1, ifcnt 232, reads 48769, writes 12, timeouts 0, DMA errors 0, CC errors 0, steps req 0 done 0
Moves scheduled 0, completed 0, in progress 0, hiccups 0, step errors 0, maxPrep 0, maxOverdue 0, maxInc 0, mcErrs 0, gcmErrs 0
Peak sync jitter 3/7, peak Rx sync delay 213, resyncs 0/0, no step interrupt scheduled
VIN voltage: min 23.9, current 23.9, max 23.9
MCU temperature: min 43.7C, current 43.8C, max 44.2C
Last sensors broadcast 0x00000002 found 1 172 ticks ago, 0 ordering errs, loop time 0
CAN messages queued 4723, send timeouts 0, received 2159, lost 0, free buffers 37, min 37, error reg 0
dup 0, oos 0/0/0/0, bm 0, wbm 0, rxMotionDelay 0
Accelerometer: LIS3DH, status: 00
I2C bus errors 0, naks 3, other errors 0

@gruna-studio Not sure if it helps - everything is okay in RRF 3.3. So I just revert the firmware on both boards back to 3.3 then it runs well.

Hi,

I have a 6HC + 1LC Tool board configuration for a Voron 2.4 printer. The extruder motor, hotend heater, hotend/part fans, and hotend temperature sensor (PT1000) are connected to the tool board.

The PT1000 sensor returns the correct temperature in RRF 3.3. However, when I upgrade both the 6HC and 1LC's firmware to 3.4RC2, the PT1000 sensor always return 2000C. Is this a known bug?

Here's my config.g:

; Configuration file for Duet 3 (firmware version 3.3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.3.10 on Wed Mar 02 2022 23:23:46 GMT-0500 (Eastern Standard Time)

; General preferences
G90                                          ; send absolute coordinates...
M83                                          ; ...but relative extruder moves
M550 P"Voron2"                               ; set printer name
M669 K1                                      ; select CoreXY mode

; Wait a moment for the CAN expansion boards to start
G4 S2

; Network
M552 P0.0.0.0 S1                             ; enable network and acquire dynamic address via DHCP
M586 P0 S1                                   ; enable HTTP
M586 P1 S1                                   ; enable FTP
M586 P2 S0                                   ; disable Telnet

; Drives
M569 P0.4 S1      ; X motor direction (B motor)
M569 P0.5 S1      ; Y motor direction (A motor)
M569 P0.0 S1      ; Z0 motor direction
M569 P0.1 S0      ; Z1 motor direction
M569 P0.2 S1      ; Z2 motor direction
M569 P0.3 S0      ; Z3 motor direction
M569 P121.0 S0    ; E motor direction

; Motor remapping for dual Z and axis Limits
M584 X0.4 Y0.5 Z0.0:0.1:0.2:0.3 E121.0                         ; set drive mapping

M671 X-65:-65:365:365 Y-20:380:380:-20 S20      ; Define Z belts locations (Front_Left, Back_Left, Back_Right, Front_Right)
M557 X25:275 Y25:275 S25                        ; Define bed mesh grid (inductive probe, positions include the Z offset!)

; Microstepping and Speed
M350 X256 Y256 E32 Z256 I0                     ; Configure microstepping with interpolation   
M92 X1280.00 Y1280.00 E800.00 z6400.00         ; Set steps per mm	1.8 motors		
   
; Speeds, Acceleration and Jerk
M566 X300.00 Y300.00 Z60.00 E600.00 P1          ; Set maximum instantaneous speed changes (mm/min)
M203 X120000.00 Y120000.00 Z4000.00 E1200.00       ; Set maximum speeds (mm/min)
M201 X9000.00 Y9000.00 Z1600.00 E5000.00        ; Set accelerations (mm/s^2)

; Motor currents
M906 X1200.00 Y1200.00 Z1200.00 E513.757 I60        ; Set motor currents (mA) and motor idle factor in percent 
M84 S600                                     ; Set idle timeout

; Endstops for each Axis
M574 X2 S1 P"!0.io0.in" 					 	; Set X endstop controlled by switch
M574 Y2 S1 P"!0.io1.in"                      	; Set Y endstop controlled by switch
M574 Z1 S1 P"0.io3.in"                          ; Set Z endstop

; Stallgaurd Sensitivy (maybe use to pause print after crash)
M915 X S2 F0 H200 R0		                ; Set X axis Sensitivity  1.8 motors
M915 Y S2 F0 H200 R0		                ; Set y axis Sensitivity  1.8 motors


; Mesh Grid 
M557 X5:280 Y30:250 P4                         ; 

; Z Probe Offset (Probe behind Afterburner)
G31 P1000 X0 Y25 Z1.367

; Axis Limits
M208 X0 Y-2 Z0 S1                             ; set axis minima
M208 X300 Y301 Z260 S0                       ; set axis maxima


; Heatbed Heaters and Thermistor Bed 
M308 S0 P"temp0" Y"thermistor" T100000 B4138 ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out1" T0                           ; create bed heater output on out1 and map it to sensor 0
M307 H0 B1 S1.00                             ; enable bang-bang mode for the bed heater and set PWM limit
M140 H0                                      ; map heated bed to heater 0
M143 H0 S116                                 ; set temperature limit for heater 0 to 115C

; Fans Electronic compartment & Exhaust
; M950 F1 C"out3" Q100				    ; Creates Case Fan 1
; M106 P1 T40 S150 H0                 ; Case Fan 1 Settings (Turns on at 60°C tool temp) at low speed
; M950 F2 C"out4" Q100				    ; Creates Case Fan 2
; M106 P2 T40 S150 H0                  ; Case Fan 2 Settings (Turns on at 60°C tool temp) at low speed
; M950 F5 C"out2" Q100				    ; Creates Case Fan 2
; M106 P5 T95 S50 H0                  ; Exhaust fan

; Filament Runout sensor
;M950 J4 C"io5.in"               ; Input 4 filament sensor
;M581 P4 T2 S1 R1                ; Filament Sensor P4 triggers  inactive-to-active edge (S1) tigger2.g (T2) only when printing (R1)
;M591 D0 P1 C"io5.in" S1			; Filament Sensor 



; Tool 0
; HotEnd Heaters and Thermistor HotEnd      
M308 S1 P"121.temp0" Y"pt1000"               ; define E0 temperature sensor 
M950 H1 C"121.out0" T1 Q100					                            ; Create HotEnd Heater
M307 H1 B0 R2.310 C158.7:115.4 D5.24 S1.00 V24.5					; PID
M143 H1 S315                                                    	; Set temperature limit for heater 1 to 285C HotEnd
M302 S185 R185			

; Select inductive probe, OMRON TL-Q5MC2-Z

; P4:       connected to Zmin SIG and GND
; I0:       P4 expects NC, TL-Q5MC2-Z is also NC
; T18000:   Move to probe points at 300mm/s
; F1200:    Probing Speed: 20mm/s
; H5:       Dive height: 5mm
; A5 S0.01: Perform up to 5 touches until change is below 0.01mm
; B1:       Turn off heaters while probing

M400
M98 P"/macros/Home/use_z_probe.g"
G31 T8 P500 X0 Y25 Z3.45 ; inductive probe offset, not critical, only used for coarse homing
G4 P200

; Accelerometer
M955 P121.0 I20

; Fans Hotend + Part
M950 F1 C"121.out1" Q100				; Creates HOTEND Fan
M106 P1 T45 S0.8 H1                 ; HOTEND Fan Settings
M950 F0 C"121.out2" Q100				; Creates PARTS COOLING FAN
M106 P0 H-1                         ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off PARTS COOLING FAN

M563 P0 S"Tool 0" D0 H1 F0                            ; Define tool 0
G10 P0 X0 Y0 Z0                             ; Set tool 0 axis offsets
G10 P0 R0 S0                                ; Set initial tool 0 active and standby temperatures to 0C

; Custom settings are not defined

M501										; Load overrides