Hello. Welcome to Just
When wiring a hot tub to the double pole GFI breaker, the breaker's white pigtail goes to the neutral bar.
But the white wire that goes out to the tub needs to be on the double pole GFI breaker. There is actually a silver terminal screw, typically with a small area of white paint near it, which is there for your load neutral.
The hot tub is the load, so its white wire needs to be on the GFI breaker, at the proper terminal.
I knew it was some think simple I was missing out on. That worked thank you Jason.