I didn't read through ALL of the older posts, but for situations where lights seem to trip the GFCI, ferrite cores/chokes can be a solution. Simply put, some AC devices and lights (in my experience it was T5 ballasts) can emit electromagnetic and radio frequencies (EMI/RFI) that the GFCI misinterprets. Adding a ferrite core to the power cord can help with this.
(*I was advised by an electrician to use these on my previous T5 fixture and it worked; YMMV, and I welcome any input regarding this application)
(*I was advised by an electrician to use these on my previous T5 fixture and it worked; YMMV, and I welcome any input regarding this application)