Just tried setting up a widget to show the remaining battery duration until charged/empty by using $tf(bi(fullempty))$.
It works well in the editor but the widget always shows “moments ago” so I removed the $tf()$ bit and only left $bi(fullempty)$, which shows fine in the editor but is empty in the widget.
Battery optimization is off, notification is showing and i confirmed KWGT was running and that the widget updated fine otherwise.
This is on a Nothing Phone 4a pro running Android 16/Nothing OS 4.1