A very strange bug was reported on GITHUB…
It appeared that the PWM function of the modules was never starting, and the side effect of this was the module would attempt to bypass/enable the resistor load but would stop at 10 degrees below the setpoint. The RED LED would blink on every now and again.
This was resolved by upgrading to the latest version of platformio and visual studio code
VS Code
Version: 1.51.1
Commit: e5a624b788d92b8d34d1392e4c4d9789406efe8f
PlatformIO 5.0.3