Yea had problems with this my self, used over 40 pristine matches on different locations, including indoors, outdoors, on a hill, in a gully, the only common factor was that I was soaking wet at the time. Yet it reported excessive wind, as the cause.

I can confirm that attached weapons flashlight in hardcore are not functioning, and add that if you hot bar the flashlight, and click it to put it in your hand, it will function normally, both pistol and weapons versions, pristine and worn.