Hey Joe - great content in your reply. It shed some light into why I'm seeing this behavior.
Your initial point on the playtime threshold value was spot on. It was set at the default value of 30m. The play time value for this game was 4 seconds. Meaning every time I finished playing a session, it would revert the progress value back to 'Not Started / Unplayed'.
So that brought up another question. Why does this game not accrue all the play times? I've got at least 30 hours invested in this game. As a DOS game, I'm using SCUMM VM as the engine (not DOSBox).
To test your line of thinking, I manually entered "100000" in the game's play time value in the MS-DOS.XML file and saved it. I went through the steps to re-create the issue I noted in my initial post, and the problem did not happen again. 😁
So, at this point, there's a workaround in place. Thank you.
To answer your last query "Where exactly are you finding the "\XML\ folder?", it's the last directory off the install directory root, right after directories named 'ThirdParty', 'Updates', and 'Videos'. However, the MS-DOS.XML file that I updated with the play time value was located in the \Data\Platforms directory.
Chris
CardinalBass2112's post in MS-DOS.XML File is Getting Over-Written with Old Data was marked as the answer