Its interesting how the teeth marks disappear for some distance just prior to the notch cut into the filament. I would have expected to see the teeth marks continuing all the way to the notch. Otherwise, how was the filament being moved?
The hobbed bolt carving into the filament is something pretty much everybody runs into at some point, and people have identified all sorts of reasons for it happening on their machine. FWIW,
Extrusion Problems is a post I've kept current with what people have found. Some of the info is specific to the Greg's Wade extruder on an i3v, but a lot of the info is generic. For me, it's typically been caused by filament with bulges in it that can't feed into the hot end or retraction settings being too aggressive on fine-detail objects.