I would change guns temporarily, until I'd determined what the problem was. I've had malfunctions caused by broken parts, worn parts, bad ammo, etc., and if I can determine what caused the problem I'll fix it and carry on.
The vast majority of malfunctions that I have had were undetermined as to cause, since they're not chronic. If I had three similar failures in 100 rounds, I'd definitely have to determine what was causing it, and fix it. Three failures in 1000 rounds would concern me, too. I have gone 1000 rounds without failure many, many times, but don't know if I've ever gone 2000 rounds, in any gun with that many rounds through it, without at least one failure of some kind. I don't think there's any way to isolate, diagnose and repair random failures that occur every 1000-1500 rounds; there are just too many variables.