I open a jpeg file in AP & do nothing other than drag the Blur Brush Tool across the edge of the single pixel layer it contains. I then select File > Save & get a warning that the file contains non-pixel elements, with an offer to save flattened, save as, or cancel.
Thing is, even if I cancel & then from the Document menu select "Flatten" I still get the same warning if I try to save the file.
If I use the Blur Brush Tool but do not brush past the edge of the document, I do not get the warning & the file saves without issues. This does not happen with other pixel tools like Sharpen or Smudge -- I can drag them past the document edges without getting the 'non-pixel elements' warning on Save.
Anybody else seeing the same thing?