Steps to reproduce
Using a keyboard with a layout that does not have the comma key in the same position as this diagram of a QWERTY keyboard
Post > New Work
In an autocomplete field like Additional Tags, do one of the following:
enter some text and press the comma key on your keyboard
enter some text that uses the key in the same position as the QWERTY keyboard's comma key (e.g. ת on a Hebrew keyboard)
If you press the comma key on your non-QWERTY keyboard, a comma appears in the field and nothing else happens. You'd expect it to finalize the entry of the tag, making it appear over the field the same way pressing the comma key on a QWERTY keyboard does.
If you press the key that's in the same position as a QWERTY keyboard's comma, it finalizes entry of the tag, making it appear above the field. This effectively prevents you from using whatever letter/character is on that key. You'd expect to be able to use that letter/character normally. (If you're using a QWERTY keyboard, you can also see this behavior by trying to use the < character, which requires you to use the comma key in combination with the Shift key.)