Smooth PEI coating lifting at corners of print

Hey all,
I do some 3D printing on the side as part of my job but I seem to be having an issue with the smooth PEI coating lifting at the corners of some prints, as I have to print the same pieces on a fairly regular basis to maintain stock and it seems the PEI sheet doesn’t like this. It can cause the corners of the print to lift a little.

I can sort of “reset” the PEI by putting the smooth PEI layer face-down and heating the bed, for a while but after 1 print the coating starts lifting, and the corners will occasionally lift on the 2nd print.
The main issue seems to be with sharp-ish corners.

I clean the bed between every print with 99% isopropyl alcohol.
We exclusively print with Black Polylite PLA.
We’ve been keeping the printer in a separate enclosure has definitely helped in the colder months, but the lifting issue is still becoming more of an issue, especially the more we need to print this part.
I would swap to the textured layer, but the sharper corners seem to lift in a similar manner, sometimes worse. I would use a brim, but the base of the part is just about 1mm away from the supports on both the inside and outside, and I don’t want the supports to fuse to the product, requiring me to use a knife or razor to remove it.

Does anyone have any advice to get the PEI layer to stay adhered to the steel bed. Or do I just need to start rotating the part by 15-20 degrees every few runs, to avoid hitting the same spots over and over?
Any additional suggestions would be greatly appreciated.

I have a print of this part currently running after printing some on the textured side, I’ll see if I can get some pictures of the adhesion issues of the PEI layer tomorrow once it’s done and i have the chance to pull it off the bed.

Thanks in advance!

I am guessing it may be an issue with the glue that holds the PEI layer onto the steel plate dissolving from the isopropyl alcohol. I am guessing that now with no glue, the edges are being pulled up by the prints. Just use dish soap and water instead, and probably get a new plate.

The glue deterioates with heat. That is something we cannot prevent. Some even worse with tiny air bubble that expands when heat up.

I guess, just have to buy different plate or use textured plate