Weird behaviour trying to edit PDF - Arabic numerals substituted
I am having issues recently when trying to make edits to existing PDF's.
For example, with a simple bit of text like this (in Calibri font, nothing exotic):

I can change a bit of the text like this:

But as soon as I attempt to change or add any numeric characters I get Arabic numerals:

I have uninstalled and re-installed Acrobat. I also tried setting the Default font for Text Editing in Preferences. Neither made any difference.
I am using the latest version of Acrobat for Windows (v23). I have Windows 11 also latest patches applied.
I am editing PDF's on the SAME computer that I created them with. So all fonts used originally are available when editing.
What on earth is going on!! Thanks in advance.
