3.5beta2 EndstopMonitor plugin does not start

[oliof]

Hi,
currently testing 3.5b2 and bringing up a machine on a new board, I am trying to install the EndstopMonitors plugin. It installs fine, but yields an error

I also note that this error is not in the console and as such is hard to copy and paste. Sorry for the image.

Is this expected, or should 3.5 refuse to install a plugin that isn't compatible? Or should this work?

Duet Web Control version: Duet Web Control 3.5.0-beta.2

M115:

 3/6/2023, 1:02:59 PM 	M115
FIRMWARE_NAME: RepRapFirmware for Duet 3 Mini 5+ FIRMWARE_VERSION: 3.5beta2 ELECTRONICS: Duet 3 Mini5plus WiFi FIRMWARE_DATE: 2023-02-08 17:42:04

M122

M122
=== Diagnostics ===
RepRapFirmware for Duet 3 Mini 5+ version 3.5beta2 (2023-02-08 17:42:04) running on Duet 3 Mini5plus WiFi (standalone mode)
Board ID: 20ZJU-P196U-D65J0-40KM6-KS03Z-ZD7N0
Used output buffers: 1 of 40 (18 max)
=== RTOS ===
Static ram: 103012
Dynamic ram: 125052 of which 12 recycled
Never used RAM 13636, free system stack 200 words
Tasks: NETWORK(notifyWait,16.2%,230) HEAT(notifyWait,0.0%,357) Move(notifyWait,0.0%,359) CanReceiv(notifyWait,0.1%,773) CanSender(notifyWait,0.0%,335) CanClock(delaying,0.0%,349) TMC(notifyWait,0.7%,105) MAIN(running,82.0%,447) IDLE(ready,0.2%,30) AIN(delaying,0.8%,263), total 100.0%
Owned mutexes:
=== Platform ===
Last reset 00:05:27 ago, cause: power up
Last software reset at 2023-03-06 12:57, reason: User, Gcodes spinning, available RAM 11264, slot 1
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00000000 BFAR 0xe000ed38 SP 0x00000000 Task MAIN Freestk 0 n/a
Error status: 0x00
MCU revision 3, ADC conversions started 328327, completed 328326, timed out 0, errs 0
Step timer max interval 1491
MCU temperature: min 25.2, current 29.0, max 29.0
Supply voltage: min 24.0, current 24.1, max 24.1, under voltage events: 0, over voltage events: 0, power good: yes
Heap OK, handles allocated/used 0/0, heap memory allocated/used/recyclable 0/0/0, gc cycles 0
Events: 0 queued, 0 completed
Driver 0: standstill, SG min 0, read errors 0, write errors 0, ifcnt 11, reads 17200, writes 11, timeouts 0, DMA errors 0, CC errors 0
Driver 1: standstill, SG min 0, read errors 0, write errors 0, ifcnt 11, reads 17200, writes 11, timeouts 0, DMA errors 0, CC errors 0
Driver 2: standstill, SG min 0, read errors 0, write errors 0, ifcnt 10, reads 17201, writes 10, timeouts 0, DMA errors 0, CC errors 0
Driver 3: standstill, SG min 0, read errors 0, write errors 0, ifcnt 10, reads 17200, writes 10, timeouts 0, DMA errors 0, CC errors 0
Driver 4: standstill, SG min 0, read errors 0, write errors 0, ifcnt 11, reads 17200, writes 11, timeouts 0, DMA errors 0, CC errors 0
Driver 5: not present
Driver 6: not present
Date/time: 2023-03-06 13:03:31
Cache data hit count 652577733
Slowest loop: 17.10ms; fastest: 0.15ms
=== Storage ===
Free file entries: 20
SD card 0 detected, interface speed: 22.5MBytes/sec
SD card longest read time 3.8ms, write time 2.5ms, max retries 0
=== Move ===
DMs created 83, segments created 0, maxWait 0ms, bed compensation in use: none, comp offset 0.000
no step interrupt scheduled
=== DDARing 0 ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== DDARing 1 ===
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, chamber heaters -1 -1 -1 -1, ordering errs 0
=== GCodes ===
Movement locks held by null, 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
File2 is idle in state(s) 0
Queue2 is idle in state(s) 0
Q0 segments left 0, axes/extruders owned 0x0000000
Code queue 0 is empty
Q1 segments left 0, axes/extruders owned 0x0000000
Code queue 1 is empty
=== CAN ===
Messages queued 2979, received 13116, lost 0, boc 0
Longest wait 28ms for reply type 6042, peak Tx sync delay 5824, free buffers 18 (min 17), ts 1637/1636/0
Tx timeouts 0,0,0,0,0,0
=== Network ===
Slowest loop: 41.20ms; fastest: 0.00ms
Responder states: MQTT(0) HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)
HTTP sessions: 1 of 8
= WiFi =
Network state is active
WiFi module is connected to access point 
Failed messages: pending 0, notready 0, noresp 0
WiFi firmware version 1.27
WiFi MAC address f0:08:d1:02:e9:33
WiFi Vcc 3.40, reset reason Power up
WiFi flash size 2097152, free heap 23504
WiFi IP address 192.168.86.47
WiFi signal strength -58dBm, mode 802.11n, reconnections 0, sleep mode modem
Clock register 00002002
Socket states: 0 0 0 0 0 0 0 0