In case someone else runs across this. I had a very similar issue with the Atom S3 Lite not working with the PWM Kit. There is a voltage select 0ohm resister link for the PWM driver. It's labeled 5v and 3v3 just above header pin 21. As shipped the 3v3 is bridged to the center pin. This powers the PWM driver chip off the 3.3v pin of the atomS3. This causes lockups and very intermittent wifi. I removed the resister and bridged 5v to the center pin. All issues went away and everything works normally.