I’ll start by asking the obvious question before we dive deep into troubleshooting:
Could it be that your filament has gone bad - for example, due to moisture, sunlight, or something else? Does this happen with every PLA filament, or just with this one?
What does the print look like when you use a different filament?
I’ve taken that information into account, but for now I’m just going to focus on PLA. Step by step. What happens if you use a different roll of PLA filament? Does it look exactly the same?
You could also quickly check what your extruder gear looks like - it’s a quick process. As far as I know, the P1S doesn’t come with a hardened steel extruder gear assembly. You didn’t mention how old your printer is, but that could be the cause of the problem. Or as bambu says:
“If abrasion or clogging occurs due to extended use, users can just replace the extruder gear assembly rather than the whole extruder unit.”