I am not able to reproduce either. Given that this was submitted 4 years ago, I cannot recall exactly what I saw before but things seems fine based on my repro steps. Thanks!

On Mon, Sep 6, 2021, at 05:25, Lars Ingebrigtsen wrote:
> Donald Curtis <dcurtis@milkbox.net> writes:
> 
> > # Odd Behavior
> >
> > 1. open `sample.el` with: emacs -Q sample.el
> > 2. eval the `defadvice`
> > 3. eval the `progn` portion of the provided code.
> > 4. transient mark something
> > 5. hit C-.
> >
> > now the active-mark disappears.
> >
> > AND what is even weirder is that if you remove the `compile` option from
> > the `defadvice` then there is no issue. but there is something weird here!
> 
> (I'm going through old bug reports that unfortunately weren't resolved
> at the time.)
> 
> I tried reproducing this problem with Emacs 25.1 (and Emacs 28), but I
> was unable to -- the active region didn't disappear.
> 
> Are you still seeing this issue in recent Emacs versions?
> 
> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no
>