When the Runcam Split 2 in my XHover MXP200 miniquad started dropping frames, locking up and failing to record it was time to throw it on the bench and take a look.
Having now flown the quad/camera more than 15 times since the repair I'm pretty certain that the problem was related to the flat-flex camera cable and its connection to the main PCB. Everything seems rock-solid again and I'm happy to call this one "fixed".