A leak that appears in the same place even after replacing the back seals suggests the problem may not be the A12 insert seals alone. On Hasselblad V-system bodies, a known cause is the auxiliary shutter/light baffle at the rear of the camera body: the two flaps must close tightly together to block stray light, including light entering through the viewfinder path. If they do not meet snugly, light can reach the film plane and create a consistent leak.

The edge damage on the back could also contribute, especially if it lines up with the leak, but based on the reported repair experience, the improperly closing auxiliary shutter is a likely culprit to inspect first. As a quick diagnostic, temporarily taping the suspected exterior gap can help confirm whether the back damage is involved. If the leak persists, the body’s rear shutter/baffle mechanism likely needs adjustment or repair.