Which font is that?  I cannot reproduce with the default font Emacs
uses here.  Do you see the same results with all monospaced fonts,
once you customize the comment face to use italics?


Source Code Pro, but it doesn’t seem to be relevant.

I have been able to reproduce it with a minimal setup (see the
attached screenshot):

(setq inhibit-startup-screen t)
(setq fill-column 80)
(global-display-fill-column-indicator-mode)
(custom-set-faces
 '(default ((t (:height 160))))
 '(font-lock-comment-face ((t (:slant italic))))

The problem is that it doesn’t always happen, I had to restart emacs
many times (I’m doing `emacs .emacs.d/init.el` one time after another)
until the issue happened. Due to the random nature of the issue it’s
not possible to ascertain that the (:height 160) part is strictly
necessary, but let’s say that I’ve rejected the null hypothesis that
the issue happens at default font size, but maybe it’s that I’m
shortsighted enough as to not perceive it at the smaller font size.
BTW, the default font in my system is Menlo.

Best regards,
Carlos