It was doing it before I ever plugged the keystep, just pressing the trigger button. This is absolutely an issue with low power I think. It's in a new case now that has a beefier power supply and is working flawlessly. Thanks for your help!

UPDATE: Tried it in a different case and it seems to be good so far.... I guess the TipTop Zeus wasn't really providing enough juice for the module?

Hey Jason Yeah so turning the sustain to just past 12 prevents the dive from happening until you let the keys or the trigger button go, then it happens if the Release is anything but non zero. Here's a video showing what I mean: https://drive.google.com/open?id=1SEBoCqrAN4jPrwARSsoV2FUBpWD7Xzko&usp=drive_fs

Just upgraded to the latest firmware and it's STILL happening - this sickening pitch bend.

PS. I've also tried the reset procedure by turning off and holding shift while it powers up. It's still doing this pitch down thing.