Has anybody seen this "incompatible data" error when installing rom using Flashfire?

I recently purchased a fire 7 which came with fireOS 5.1.4 on it which I downgraded to 5.1.2 (verified version in settings). I used KingRoot to get root and have verified that apps require root are working. I installed Flashfire and everything appears to work fine until I select flash. I can see it does the wipes fine, but when it tries to install cyanogenmod I receive an error that says "can't install package on top of incompatible data."

I have reset the device to factor defaults in settings and tried again and received the same error. Has anybody seen this issue before in flashfire? I've been looking for some time now and I seem to be alone.