Looks like a filament runout sensor, and there is a tiny tiny little bit of extra filament sticking out the top right. If the print had needed a little bit more filament, it would have pulled through the sensor and the machine would have reported it had run out of filament and paused the print.
Essentially flying really fucking close to the sun and somehow making it by the skin of their teeth.





Yeah I discovered this when I went to print a frame stiffener mod and only had the parts to install half of it… was utterly confused as to why the prints were failing, then realised that what was happening.