Strange line-spacing in headers?

[Lars-Johan Liman]

Hello gentlepeople!

I get my Emacsen from emacsformacosx.com and just upgraded from
Emacs-28.2 to Emacs-29.2 on macOS Ventura.

I immediately realized that someone had been playing havoc with fonts.
It took me a bit of research to find

(custom-set-faces
 '(gnus-header ((t (:inherit fixed-pitch)))))

That "kind of works". I do get the fixed-width font I want ( = my
default font), but the line-spacning in the displayed headers
(To/From/Subject) is different than the line-spacing in the message
body. In the header, the lines are further apart.

I wonder if that's inherited from the GNUS default font, rather than
from the font I've configured? I cannot find where it's adjusted. Does
anyone of you happen to know?

... or should I approach this in some totally different way?

I append a screenshot for illustration.

                                Best regards,
                                  /Liman