Switch Pro Controller and Joy-Con sticks aren't calibrated properly

[seanmcnally98]

On iPhone 12 Mini, using both a pair of gray Joy-Cons and the Switch Pro controller. All the buttons work fine, but the sticks don't work properly to emulate d-pad button presses. Using a separate app which tests controllers, I can see the sticks themselves are working properly with the phone, but something in Delta is not recognizing their input properly.

See an example of what I mean here: https://www.youtube.com/watch?v=GSK30DPh-us