Large VTOL motor shutdown right before takeoff


I’m working on an experimental project, building a Nimbus Pro tilt rotor VTOL, we are having some issues getting it to take off in quad mode though. Everything appears to be setup correctly in mission planner (followed all the documentation on settings for VTOL aircraft) but when we go to take off we are getting significant oscillations and it sounds very rough (already reduced the Pids by 1/2 didn’t help). Also it seems that just before lift off thrust is reached the front motors shut off, any ideas? We know we have enough thrust, we got it to lift of briefly by setting It in a ~25* nose down attitude on the ground. Video here: Large VTOL issues - YouTube

I can upload logs in a bit

Thanks in advance for any help/thoughts!