I work on spas for a living but not an electrician an electrician installed a 50 amp ground fault breaker at the spa it trips as soon as cut on we checked all electronics on spa no problem I think breaker is wired wrong also box inside is a 30 amp breaker electrician tied to.

A popular miswire issue is how the neutrals are connected at the GFI breaker, causing the GFI to trip.

This assumes there is no preexisting ground fault in the spa wiring.

The 30 amp breaker at the panel feeding the 50 amp at the spa is probably incorrect, and needs to be changed out to a 50, assuming this is what the spa needs.