I joined this forum to post about just this exact squeak, but didn't have a good way to record it (and was figuring out how to describe it). I was figuring it was a "figure out where to grease" sort of problem, so didn't even think to look back with the filament. I don't have it permanently fixed, but taking some tension off the filament seems to stop the sound until it's fed a bit more and re-tightened the line. Once I have some time, I'm sure this can be sorted for a longer term fix. Anyway, I mainly wanted to come over and say thanks for posting the video and helping to fix my issue over here, too!