I have done this before and forgot what shortcut keys I hit. I had LO configured to paste the actual date in documents, which I placed using my own shortcut key - and there are thousands of dates - but now “date (fixed)” is what is shown in all the date fields, despite trying to edit the field, though I can choose “date” which only results in “date” being shown in all the fields.
Page numbers also are not shown, as just “page number” is instead.