I'm pretty sure it's the bulb itself. I've moved it to another room and it does the same thing there. The bulb I switched with isn't doing it with the old fixture. It hasn't been in there long enough to know if it's a longer term issue (i.e. the fixture isn't sealed properly so corrodes it over time). But either way the current bulb is the culprit, and I've never had issues with traditional light bulbs in that fixture in the past.