(this is probably an obvious ‘duh’ post for most people)
15 year old house here. All switch receptacles have neutrals and grounds, but none of the switches had the grounds connected. I figured since the old switches didn’t need them, these wouldn’t either.
In two instances (installed 10 of them), the switches would power up, but would flicker and sometimes reset seemingly random. After trying everything I could think of (wrapping anything bare with electrical tape, etc). I decided to hook up the ground and voila - everything is behaving solid.
Just a public service announcement for anyone coming across this.