Quick update on this: This was defintiely a 12.1 + Steam Client issue.
A subsequent update of the Steam client that was pushed in the last couple weeks appears to have resolved the problem.
Thank you for the response.
Good call about 12.1, I did upgrade from 12.0.1 to 12.1 on 12/31, and WFTO last worked on 12/30. That seems the likely culprit!
I've tried restarting the Steam Client, rebooting, and reinstalling WTFO.
Agreed, I'm seeing others with this error and it is almost certainly related to the Steam check, but none of my other Steam games seem to be having this issue.
Customer support service by UserEcho