On March 19, 2022 8:03:34 PM GMT+01:00, Juri Linkov <juri@linkov.net> wrote:

 Eli just fixed the real issue in the display engine. So now your code
 does not need to force the update. BUT it still needs to set the

 (setq-local cursor-face-highlight-nonselected-window t)

 in completion-setup-function... I can do it for you unless you prefer to
 add your own function to completion-setup-hook.

Maybe better to set a new window parameter in the command that navigates
completions from the minibuffer.  Then such a window parameter could be
checked in redisplay--update-cursor-face-highlight.