Following. Got the same problem after i updated to reprap 3.2.2 firmware and duet webcontrol 3.2.2
Just changed the heater also and a new fan blower so need to to the pid autotune also. But mine also fails.

Warning: heater behaviour was not consistent during tuning
Auto tuning heater 1 completed after 3 idle and 25 tuning cycles in 1410 seconds. This heater needs the following M307 command:
M307 H1 R2.206 C141.4 D8.27 S1.00 V24.0
Send M500 to save this command in config-override.g