Accessing and using Microsoft Teams on smartphones and tablets across platforms
For those who are still having the problem, you need to be on:
Teams 1416/1.0.0.2021042002 (regular version)
Authenticator Beta 6.2105.2880 (need to sing-up for beta releases)
After you install the new Authenticator, clear the Teams App Data. This was the piece I was missing to finally solve the issue. It has been solid for the past 3 days.