If you have a hand-lens or magnifying glass handy, simply looking carefully at the filament will very likely reveal a break in it, if it exists.

The wound (spring-like) filament can certainly have a break in it but still illuminate intermittently, when the ends happen to meet.

For the cost, x 3 on replacing the globe.
But you could just SWAP with one that shows no abnormal behaviour.
Then you'll know.