Hi guys! Im new to this app and had the same issue. I tried by looking into the preferences folder and checked if all files had permission to be read & written. These settings look to be okay.
Then i tried something else. On my MacBook pro giving return, it does allow the edit to be saved. But if you use CMD + Return, so its an enter then mimicking a Numpad enter i believe, then it does save.
See below first try was a return, the second one using CMD + Return... WORKS :)
PS fn + Return also works. So seems the return is bug, doesn't register it but does register the enter key. Where do we post bugs, i cant seem to find a section for that?