Strange Nozzle Behavior

I've been printing from the same roll of PLA (my first) for a couple of weeks with no issues. Suddenly, at the point where it's just about to print and normally a string of filament comes out and falls to to bottom, it makes a clicking sound similar to when the extruder is jammed and instead of the filament dropping straight down, it comes out the nozzle and goes up and starts collecting around the side of the nozzle. If I wait for it to start and sort of grab it and draw it down, it goes on to work just fine. I don't see anything on the nozzle itself but perhaps I'm missing something. I tried using the "Load Filament" command and it works fine, dropping a straight string right down to the bottom of the printer. Any ideas?