You file a regression defect, and without it getting assigned or reviewed, it's fixed 3 builds later. What are you supposed to do at this point? The defect originator can't mark it as fixed, only invalid. It then goes on my statistics as an invalid defect.
(I wonder if their defect workflow prevents the closure from its current state.)
Is there some way to track down who made the fix that resolved the originally reported defect? Can you retroactively push the defect through the states that it should be in? Don't know if you also incorporate a time element into your defect tracking which could also be thrown off.
"The single biggest problem in communication is the illusion that it has taken place."
-George Bernard Shaw, Irish playwright and Nobel Prize winner, 1856-1950
I have had similar happen in the past - never sure if something is fixed accidentally or fixed intentionally but not documented by developer. What I ended up doing was creating a category for these, so that they were still in defect count - and they were closed but closed due to "a miracle cure" so to speak.
I have not failed. I've just found 10,000 ways that won't work" --Thomas Edison