According to Jamessa :

I don't know if it is dual or single. I will check. I'm confused, if
I remove the hot wires why would the breaker trip?

If your tub has a 240V heater and/or pump, it'll be a dual.

The hot wires are the _output_ of the breaker. If the breaker refuses
to stay armed after power is supplied to it (the main breaker via the
panel backplane) and the breaker output is disconnected, it means the
breaker is at fault. Probably the GFCI circuitry.

After a thunderstorm, the above is the most likely.

It is possible that the breaker is tripping at too low a current
(not a GFCI). You can rule that out by making sure that the tub
is 100% turned off (heater, pump off) and trying to power it up.
[Do this before disconnecting the breaker from the tub].

The "worst case" (from your perspective) is when the breaker will
stay armed with the tub completely switched off and then trips
when you turn on the pump or heater. You won't be able to tell
whether it's a weak breaker or a short in the tub. That needs
test equipment and/or experience.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.