I meant canvas size. This morning I am not experiencing this issue anymore. The only manoeuver I can remember, is that I had my original file as a 32x30, then converted it to 32x26, then saved it to a new file without overriding my existing one. Then the warnings started.
Just a theory: could it be related to the clipboard having something in memory outside of 32x26 at that moment then got confused after updating the file?