I came across this while looking to resolve a light problem. I have a 35000 gal pool that I do a reasonable job of caring for, but do not spend enough time swimming. Looking forward to learning.
Hayward has an info sheet out on Resolving GFCI Nuisance Trips. The “approved” solution is to connect a Hayward GLX-HAL-XSNUB snubber capacitor (arc suppressor) across the primary leads (line to neutral) of the transformer on the load side of the light switch or relay.