Wonder what (or how much) they changed in the components.... a 120V outlet, of course, can be on a GFCI circuit, where the EVSE/high current 14-50 isn't. But you shouldn't be seeing the kind of current imbalance to trigger the GFCI.
Have you tried resetting the GFCI? Some that don't get reset in years have issues and they should tested monthly (and almost never are).
Don't want to turn this into a general electrical troubleshooting thread, but this might be useful.
my outlet is not on a GFCI, just tied into circuit breaker at the panel...