Unravel about 1-2m of filament from the spool and check that it doesn’t have any abrasions. The grinding seems to cause them.
See AMS is grinding filament, causing errors - Bambu Lab X1 Series / Troubleshooting - Bambu Lab Community Forum
If it has them then that’s your problem now but I don’t know what the original one might be. I have a similar problem and I am suspecting it is the Y splitter I installed as I noticed it would get stuck when the filament was passing through.