I've got issues too. When it came in the box the gimbal clamp was not on and I can't get it on straight. I see the wedge and where it goes, but the clamp appears to be too big to fit properly.
The gimbal appears to work fine and looks straight. The gimbal clamp looks like all the corners on it are square, I think it just tries to wedge the camera apart from the base plate (where the SD card is).
I talked to the reseller and they said they had noticed another one where the clamp was off when they unboxed too.
Am I doing some thing wrong or is it just poorly designed? I've got a P2V+ so I know how well they should fit.
PS On closer inspection the wedge bit on the clamp appears to be too fat to fit in the slot on the camera base making it push away from the camera base by almost 1mm. I might try and sand the wedge on the clamp.