I have a CFL in the bathroom that went out on me. I’ve been too lazy to change it because there are other bulbs that are working. Well after a couple weeks, it magically decided to turn back on. It’s nowhere that it would be jostled or anything, so I found that weird.
It could simply be a loose connection. It will go out again.
This is the most common one for me for both CFL and LED bulbs. The smooth connection on the base just doesn’t connect as well as the kinda rough old incandescent bases and I have had to gently pull on the little tab it pushes against in the mount to get a better connection.
Have one in the bathroom that I messed with earlier this week after the bulb started practicing for a horror movie.