Curious, there’s no reason that I can imagine for it, but if I save the same image as a jpg on macOS with 4.4.0, there’s no dc:creator metadata entry, while when I do that with the Linux appimage, there is. Looks like a bug.
In general, the metadata system in Krita is pretty old and suffers from having started out as a research project, back in 2007. I’m not surprised there are bugs…