Huge thanks to everyone who posted. This sub is awesome. Based on what I’ve been advised here, I’m going to plug the lights in the GCFI outlet that I know is working properly. If that trips, I know the issue is somewhere in the lines and I’ll eliminate and recheck until I locate it.

If it does not trip, I’m going to plug a hair dryer into the suspect gcfi and see if that trips. If it does I’ll proceed to replacing the outlet.