I've tried other various feeder helpers for my P1S but still got errors when swapping filaments about can't pull back filament. I noticed that if I straightened out the bowden tube where it enters in the top of the extruder then the filament would be able to pull back. So I designed a newer, taller filament feeder guide for my P1S. I've been running it for the last 5 days without that getting that pull back error message so far. As with all these mods your milage may vary. Hopefully it will help for some of you all. Also, I tested this in all the positions on the bed and it does not interfere with the drag chain in anyway.

Cheers