In Calc 9’s in courier shown as dashes

Mac OS Version 10.15.4

Just upgraded to 6.3.5.2 on Mac. In Calc in all my spreadsheets, 9s are replaced with dashes. When I replace Courier with another font 9 shows normally. Is this a bug? I don’t really want to replace the fonts and reformat all the spreadsheets I’ve been using for years.

on Mac

Could you please provide the exact version of your macOS?
When you open a spreadsheet, does the font appear as Courier (i.e. in italic) instead of Courier in the Font Name box?

Opaque,

Added Mac OS version in OP.

Solved the problem by resolving a duplicate font in the system Font Book. (At least that’s what I think solved it.) I can’t say for sure if Courier was appearing as Courier in italic because I didn’t open the file for a second look until after I was in Font Book.