Odd rules engine error in certain challenges

[gnomefry]

Hello. I've been spending time working through the challenges. They are a blast! I'm enjoying them as much as Shandalar. Thank you Salbei for incorporating these into the game.

I've recently been encountering the error message "gauntlet: X, challenge: Y". The X/Y values vary. The message is clickable (screenshot attached) and usually pops between 2 and 8 matches deep in Pit Fighting (set 4, challenge 2).

In this screenshot the gauntlet/challenge values are 2/0 but I've gotten others. Always referencing gauntlet 2 or higher, never gauntlet 1. The message is clickable. Upon clicking it takes me to standard loss screen.

Besides Pit Fighting, the other challenge in which I've encountered this error is "That's Big" (2-3)

Things I've tried and still gotten the error:

Different decks. Different versions (both EMN and BFZ). Beginning the challenge after a fresh re-launch of the game.

I've also made sure the deck contents are legal. But I don't think that's it. Violating the vintage/legacy rules (at least on any other challenge) generates a loss either immediately or at the beginning of the second match and does not include the clickable gauntlet:X, challenge:Y error. I gotten this error as early as the 2nd match but also as late as 8th.

I'd love to be able to play through this wonderful added content. Any ideas about the error and how to mitigate?

Thank you so much!