I recently ran power to a small shed in my backyard. I extended a 15amp circuit that was powering only a gate motor. The #12 wire enters the shed and transitions to 14/2 Romex at a disconnect. The circuit is very simple: it feeds a GFCI receptacle (first image) then passes to a single pole light switch (second image) that switches hot wire to a standard receptacle with a fluorescent shop light plugged in (third image).
Everything is wired properly and works fine, except the fluorescent shop light plugged into the standard receptacle at the end of the circuit causes the GFCI to trip when turned off (most of the time). I have tried plugging the light directly to the GFCI with no problems. I have tried replacing the shop light with a small 60 watt light with no problem. I have tried replacing the shop light with a small air compressor with no problem. It seems to be this shop light causing it to trip when plugged into an outlet downstream of the GFCI. I'm at a loss on what to try. Could it be a bad GFCI? Why is it only this scenario causing it to trip?