S8+ Battery Temperature Too Low

A

AC Question

Hi, I have an S8+ here in work, needed a display change and now the phone says battery temperature is too low. I've tried a new charge flex, display, battery and even a brand new board.
I've tried with the phone fully assembled (middle chassis screwed down & fingerprint sensor connected) but still get the same error.
Anyone had anything similar? I'm thinking it may be the chassis somehow, but don't have access to another right now.