Failing shutters are not exactly "common" ... but shutters do wear out over the life of a camera (most cameras seem to have a mean-time-between-failure of around 100,000 actuations ... with some cameras doing more like 150k or more). But a shutter failure, while rare, can happen at any time.
The pattern in your image does match what I would expect with a failure. The shutter "curtain" or "door" is actually a series of flexible blades that slightly overlap each other and slide up/down like window blinds. If one jams, it typically goes askew on an angle instead of remaining horiztonal and you end up with a spikey/wedge-shaped section of bright light much like you see in your image.
If you want to see a slo-motion of the shutter in actcion, you can see an example here, and you'll get a clear idea of how the shutter "curtains" work (they do not show a jammed shutter blade).
Tim Campbell
5D III, 5D IV, 60Da
I am in Indonesia and have what I believe is a shutter issue? Can you confirm it is a shutter issue and is this comon?
