I have a nearly identical setup. I run my spa at 101, and I do turn my swcg OFF during spa operation. If I don't turn it off first, I get that strong chlorine smell when soaking. Try giving that a shot maybe?

After I'm done, I set it back to 50/50 and let the water mix. The next day I test and adjust the pool water chemistry as I normally would.

The pH and TA may be off in the spa water but it's been through the filter a lot more than the rest of the pool water. I consider it a wash.