Mine were clearly worn on slot one. I replaced them all since I was in there. Also replaced the PTFE from buffer to my y-splitter since it seemed worn as well. I’ve had mine for maybe 4 months but have run a lot of filament through. I discovered the wear while looking for a broken piece of filament (was none).
I can’t say that’s always the problem but it seems to have fixed my issue. Good luck, hope it’s resolved soon.