OSK using incorrect mapping for Persian layout
When setting up a Persian keyboard layout in GNOME Settings, the normal keyboard input (using the physical keyboard) will produce ک (U+06A9, "Arabic Letter Keheh" in Unicode terms) when using the ":" key as it would appear in an English US layout/keyborard (the one to the right of "L") as expected. But the on-screen-keyboard displays ك (U+0643, "Arabic Letter Kaf").