PixHawk 4 Octocopter Rollover on Takeoff

We are currently experiencing an issue where when we attempt to throttle up and take off, the drone itself attempts to roll over instead of lifting up. We have double check all calibration and wiring, and also ensured that the propellers are attached in the right orientation and are spinning in the right direction.
Our PixHawk is mounted upside-down and we have it configured as such in the firmware, so I don’t think that’s the problem.

Any help with this would be greatly appreciated.