I wouldn’t think a loose extruder gear would cause that either, because once it slips, I would assume it wouldn’t grip until you tightened it.
I found that it would continue, just skipping occasionally. I actually ended up calibrating mine by asking for 100mm of extruder feed, then tightening the screw just until the skipping stopped. The looser it was the more it would skip, making little clacking noises for each skip. When it was tight enough it would move quietly, and the next 100mm test came out at something like 98mm of actual filament pulled through.