Just something that happens to the filament before it separates from vibration. I typically see this on lamps close to the flippers or slings. Try not to let it go too long like that as it does generate much more heat. The filaments on older GE bulbs didn't have this issue because the filament is much beefier.

Wow that's bizarre! I'm guessing you have higher resistance somewhere along the filament that's generating much more heat and light than normal. Can you get a close up photo of this bulb? I'm fascinated to see how the filament managed to deteriorate like this and not burn out.

I think I read somewhere that it has something to do with a failing filament and its electrical resistance.

The filament is probably twisted back on itself which shortens it greatly. Same current through 1/4 of filament (or even less) is gonna burn just a tad brighter. Then poof.

May I just add that you might want to consider replacing #44 bulbs with #47.
Slightly dimmer (barely noticeable) but generates less heat and draws less current so kinder on your connectors and power supply.

I've seen bulbs get brighter,but they usually blow shortly thereafter...........

It looks like that filament is damaged...one end loose from the support wire and dangling in space.

Good choice. For anyone who needs some 44s, put up a wanted ad for used bulbs instead and offer to pay what it costs to ship. Lots of people keep the old bulbs when putting LEDs in their games and they just want them gone. I got some bulbs this way from a couple guys, one didn't want anything for them. Got a few hundred, and the added benefit to this is you can stock up on those hard to find GE bulbs that last so well in high vibration or hard to reach areas. In my bags I found several dozen of these.

I have seen this phenomenon before. Not exactly sure what it is, but Cody's explanation is probably spot on.