When the loop breaks, 17 days have passed, which means it was just a local phenomenon and the rest of the universe wasn't affected at all. Does that mean that another ship coming from the normal stream of time could have suddenly crossed the path of the Enterprise?
I suspect that any other ship in the area would have been effected by the space-time distortion. So when the triggering event occurs (the Enterprise blowing up) everything in the sector
resets to how it was the day or so prior.
Yeah, really, under scrutiny Space Phenomenon McGuffin doesn't make much sense.