PEI shred sticking to PLA prints. No info found about it.  

PEI shred sticking to PLA prints. No info found about it.

Hey everyone! 

It’s been a looooong time since I posted anything in this forum. I been printing flawlessly with my MK3S+ for over a 120 days total of printing. But this week I’ve come across this problem which I haven’t found any info about, mainly because it usually happens the other way around, prints don’t stick to the bed. But in this case it’s the opposite, the bed comes out with my prints.

I’ll start by saying I’ve been using a PEI sheet for all those 120days for a variety of materials which include PLA, PETG, TPU… and it finally got way to damaged to use for pla, so I decided to change it for a new one I had. It’s now when everything started, I printed a keychain, after calibrating first layer (z calibration), which was pretty similar to the old setting. I finished printing the keychain and got it off the plate without problem.

When I turned it arround to see the first layer finish I found out that it had taken off a little bit of the plate finish. I thought it may have been a first layer protection just because it was new. If you touched the plate it was noticeable with your fingernails the imperfections it had left. I would have assumed it was the new plate, which would have been kind of weird taking into account I was printing Pla, until I printed a TPU part in my old sheet. Same thing happened, now, it eliminates the theory about being a protective layer for new sheets. I’ve also changed the bed first layer between beds, so each sheet had their appropriate layer height. 
Now I’m left with that kind of damaged bed and no idea on what the issue can be. 
I hope the info is clear and detailed enough so ant of you can help me troubleshoot this! 
I attach some photos of the prints and the bed, just the new one because it’s easier to see. 
Thank you for helping me!