Medium format film messup? Is it the camera?

I just bought a Mamiya RB67 and i just got back my first 3 rolls shot on it from the lab. I scan at home. On all three rolls, every shot is halfway cut off by blackness as shown. Was it the camera having an issue? I’ve never seen this before.

The black is dark so it is caused by light, rather than a lack of development or masking inside the camera. the black also extends beyond the frame into the rebates - and is in the same position in each frame. I think that has to be a light leak but where? It could be in your camera but it seems to be very well defined for any light leak I have seen. It could also be the lab.
I would have a good look at the camera - the light leak (if it is that) will be towards the base of the camera. I do not know this camera but I would suspect the lower part of the film back. Both camera and film back are now rather old - do they need new foam light seals?

I had a similar issue with a Mamiya m645 which was caused by a back that wasn't closing completely. It was solved by replacing the back with one from another camera. I know your camera is quite different, but I would carefully check the back and look for any loose connections

Don't forget that there is also a rotating back adapter on the RB67 that also requires normal maintenance.
That being said, the fact that the dark area extends into the film rebate does indicate that there is a problem with the back allowing light in - not near the film gate, but rather either near the latch (most likely) or near the hinge.
It is hard to see whether all your shots are taken with the back rotated to portrait orientation or whether you have used the back in both orientations.
Do you see any difference in the band when the back has been rotated?

Does the camera have a warranty, repair or return? Since camera stores are closed, maybe someone on Photrio who is familiar with the Mamiya RB67 and relatively nearby could take a look at it, before you have to send it out for repair.

Thanks all for the replies. After putting a little flashlight into the film back and going into a darkroom, Ive identified the lightleak... fixed it up with some electrical tape in the meantime. Thanks everyone