Hmm... looks like that wasn't it. :(
Same settings as before, but with 4.1.2. Interestingly, it bailed at round 28 instead of 29. Not sure if that's significant or not.
I've been seeing an issue where WHAM will intermittently stasis right up to the round limit and then throw up its hands by declaring that it cannot figure out a combat strategy. The WHAM_safetymargin variable introduced in 4.1 seems to be intended to protect against this and setting a non-zero...