I've never seen this before.
I replaced my glass printer bed with a new one. First print that I did (some handy Chip Clips for testing!) they were stuck to the bed so solidly that when I pried them off, it actually took pieces of the glass with them! Now it MAY be pieces of just the surface coating, but it's awfully deep gouges, and looks like the glass itself actually chipped off the bed.
Unfortunately I bought this bed a couple years ago and it's been sitting in a box in a drawer for that time so I can't get it replaced, but I didn't even think something like this could happen. Got a new one already on the way so hopefully that one performs better.
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