I have just installed LibreOffice 6.3.6.2.
I use modified date in my writer documents,
Insert - Field - More fields - DocInformation
Type: Modified
Select: Date and a format.
A narrow gray rectangle is inserted.
It is the same for modified time.
When I save the document there is no change.
When I open and then save an old document,
the date is removed and replaced by the gray rectangle.
Do I need to do something more to make it work?
I’m on Windows 10 Home, version 1909, installed just two days ago.