Azure MFA SignOn Issues with ThinOS and Amazon Workspaces.

We onboarded a number of users with ThinOS 9.1.3129 and Amazon Workspaces, but they are the first group in the company to use Azure MFA instead of OneLogIn.

Seemingly at random, select users from that group will get one of 3 errors whenever they try to sign in.
A/WebUIProc/WebUIModule (1/1) [Amazon] login to broker "code://(broker code)" failed. error => Error: Input message does not contain all required fields/tags.
OR
A/WebUIProc/WebUIModule (1/1) [Amazon] login to broker "code://(broker code)" failed. error => Error: PCM returned an error
OR
If they try signing in on a ThinOS8.6 unit, there is a long delay and then the unit beeps. Despite searching the cache dump I have yet to find an error code.

Phone call and push auth doesn't work anywhere, but when these same people use the Amazon Workspaces Windows app the 6-digit tokens always do.