I was SO for Maryland State IDPA Sanctioned Match for Stage 4. I was running a shooter who I saw put a second round through the exact same hole. Upon examination you could not tell (without a magnifying glass) that the second round had gone through. But I saw the shooter line up his second shot and I saw the target virbrate at the same location where the first round had hit. The target was an IDPA paper target at about 9 yards. Upon inspection the hole was a tiny bit oval, but normally I would have not called it a hit.
I wouldn't have believed it unless I saw it myself. But with tens of thousands of rounds going downrange and master level shooters it is bound to happen sometime.
Cody