I had originally had the same issue and tried everything as stated above. Then I had found with my stock P1P that the PTFE tube was both worn as well as the attachment point to the head cable were not equal.
When my head would go back to purge position the hose/cable system would bind and start my print offset. Once the PTFE tube was changed and the hose/Cable balanced out everything printed correctly.
With the PTFE tubes being very affordable and easy to replace it’s a no brainer to replace these when you notice them starting to wear.
I just had this issue and my PTFE tubes are just fine… These printers just suck at resuming like every other printer does when it comes to starting after a pause
before reading and hoping to find a solution I just want to say I thought I was doing something wrong causing the layer shift and now see this is a known problem, at least I hope so. I also cant even think about the amount of filament I have thrown in the garbage because of this problem. My one color prints are absolutely flawless so there is something wrong with the color change, first color, first level. Wonder if there is a shift change when second color, first level? etc?
But on 2 occasions, I had an even worse effect: Once when at the beginning of the print, the head moved from front right to the rubbing area and the nozzle was too low so it scratched the whole plate (totally new).
I have to say that I am very disappointed… I opened a ticket 10 days ago and still no answer.
When I got the printer, I ran out of filament, so I changed and continued and it was perfect. I then made an update (don’t remember what the previous one was) and started seeing these weird behaviors. Currently have the latest: 01.05.02.00 (latest version).
Also checked the screw at the back, they are tight, PTFE tube moves freely and “Auto-recovery from step loss” has no influence…
Support response time has been a problem for them for a while and the A1 issue made things even worse. They said they are trying to resolve it and improve response time, but for now all you can do is wait or follow up to ask how long it will take them to respond.
Often “weird behaviors” after a firmware update (on any device) can be corrected by restoring factory settings. You will lose any filament calibrations stored on the printer, but a Factory Reset and printer re-calibration may correct your troubles.
OK, so Factory Reset brings nothing…
Then I downgraded to version 01.04.02.00, still no change.
What’s interesting is that if I pause it once, then there is an X/Y (-0.9mm / +2.4mm) shift, if I pause it again, it continues from where it was supposed to continue…
Seems like it looses its reference on the first stop, but on the next pause it keeps the reference…
It seems like it is most likely a hardware issue, not software. Have you done all the maintenance like belt tightening, cleaning and all the other things they mention in the Wiki?
After reading this post https://www.reddit.com/r/BambuLab/comments/10jvjrj/comment/j5rz43b/ , I realized that the P1S was homing without end-stop switches (even my old Ender 3V2 had some!)… And the covers where basically creating an offset when pausing in the back left corner.
So if you ever find a shift, it is probably because your machine loses its reference. So either you have to add a homing action of X-Y after every time it goes to the back left corner or find out what is creating the shift.
It still doesn’t explain why my plate was scratched, but now I understand how critical it is for the motors to move freely, without missing steps.
It’s more so 4/10 times it fails or does something it’s not supposed to and the other half it’ll function properly…
We had an issue like 2 firmware versions ago, where a specific slicer setting caused the tool head to stop every couple layers and purge - retract - feed - purge - resume… Changed some settings and it went away but I can’t remember exactly the feature, but I think it was something with wipe on loops.
I’ve experienced the X1C do crazy things… Just the other day, the bed was lowered near the bottom due to completing a tall print previously and yet when starting another print it lowered and made the grind sound hitting Z limit…
This was supposedly addressed and fixed in past firmware updates but it randomly happend and doesn’t always idk…
OMG!!! You just solved a problem that has started recently and was driving me crazy. Whenever I printed anything with a filament change with my P1S and AMS, I would get a slight layer shift and had no idea what was happening since it was not happening before.