Exif data spill into comments without any user interaction
GThumb version from Debian 10 Buster - 3.6.2
Although it did happen occassionally for some time, switching to a new camera makes this show up on nearly every picture for me so thus the bug has become more unpleasant for me.
Viewing newly imported pictures for the first time, I do not see any comments in the thumbnail browser. After having viewed the pictures individually, comments have been created that look like spill over from exif data.