bug#59122: 29.0.50; global-text-scale-adjust not working

[Gregory Heytings]

> I can reproduce this bug on macOS 12.6.1 (OP is on 12.6).
>
> After pressing '+', '-' still doesn't decrease the font size.  I can 
> only increase it using '+'.
>
> Output of C-h l:

Thanks.  What do you get when you eval

(face-attribute 'default :height)

?  And what happens when you eval

(set-face-attribute 'default nil :height (- (face-attribute 'default :height) 
5))

?  If nothing happens, can you try with 6, 7, 8... instead of 5, until 
something happens?