Spa leaks internally when jets are turned on

I'm having an issue with my spa where it leaks internally when I turn on JETS #1. I've linked a photo showing where the leaks are as well as a short video link showing the blast of water past the couplings when I turn on the jets. It doesn't leak when JETS #2 are turned on.

Any thoughts on what the problem could be and where I should start looking to fix it?

I'm not sure if it's just the coupling seals that are failing or if there's an issue downstream that's creating excessive back-pressure.

Model: Alps Q-DL

Manufacturer's website: https://alpsspas.com/models/q-dl/

Picture of spa innards: https://i.imgur.com/YPKO5Gj.jpg

Video of leak: https://www.youtube.com/shorts/KxJAa1cQxCc