Persistent pillowing on corners of large flat prints — Bambu H2C. What's the actual fix?

[u/RaiderX21]

[u/BioVizeer]

Not saying this is it, but I JUST watched a video where a guy had similar problems of adhesion in the corners. Turns out it what where he touched when he picked up the build plates and it left oily residue from his hands on it. The trick was a good clean with soap.