LED light flickering in one socket but not others, and any other bulb works fine with the socket
Notice that the base of an LED bulb (the part above the socket) is wider than the base of an incandescent.  Often, something about the fixture is making contact with the wider LED bulb, so that it binds up and prevents it from screwing into the socket all the way.  It feels like it's screwed in all the way, but it's not. 

If you look at the nub on the bottom of bulb or socket, you may see arcing marks.