The power armor doesn't go into my armor slot. It seems to disappear from my inventory.

Shift+clicking power armor while modular armor is equipped causes the power armor to disappear.

13.zip is the save file I loaded going from 15.21 to 15.23 (it's a poorly built map, don't judge me). Steps to reproduce:

Construct power armor
Shift+click power armor
???
Don't profit.