For anyone following, my issues turned out to be the pitch gyro, just as suspected. From Spectrolutions:
ORIGINAL: Spectrolutions Support
Just informing you your circuit board is repaired and on its way back to you. What we found wrong was that the pitch gyro had gone out, which explains the symptoms you were describing. Once we replaced it, it flew smoothly again. We also found a cracked trace on pin 5 of the 9-pin header which was causing your left LED to act flakey. So we reworked that area, and got it up and running again. All other systems check out great.
They're great. Can't wait to get up and flying again!