It works for me: F27.3, MBP 2018 (Intel), latest development seed of Ventura (13.2; just dropped yesterday). Not sure if it's an OS issue or not but I don't think it is. I'm going to assume you've done all the usual things (restarting Finale, restarting your MBP). Not sure what's going on in your case. Sounds like it's limited to Finale so are you at least able to use the trackpad to move the cursor where you want it and backspace from there?

Rick, I’ve never seen that one. If Support gives you insight on this, please let us know. If not, I may have some ideas.

Hi Mike.....

After working with MM support I found that this is indeed a known bug with Finale for Mac only. Specifically, if I have the Simple Entry tool selected when I do a "Save As…" the arrow keys have no effect on the file name field in the Save As… sheet (even if I click on the field). Curiously, the "Simple" menu heading in Finale flashes as I press the arrow keys. 

I do "Save As…" a lot when I'm updating versions of Finale docs I'm working on and am used to just arrowing to the right to increment the version number. I guess it just so happens that I noticed the issue when I'd been working in Simple Entry.

They say they don't have an immediate fix for it, and—as far as I can tell—it only happens when the Simple Entry tool is selected. I guess it's not just me this time!

So, if I am understanding correctly, having another tool selected when doing Save As is the workaround. Correct?

That’s right.