I'd just like to add a data point here.

I'm on Debian GNU/Linux and have experienced the same thing (though not
very often).

I lose a key, and there's a "Quit" in my *Messages*, too.

More importantly perhaps, I'm also using aggressive-indent-mode.

João

On Sun, Jun 3, 2018 at 8:23 PM, Alan Third <alan@idiocy.org> wrote:

> On Sun, Jun 03, 2018 at 06:05:36PM +0300, Eli Zaretskii wrote:
> > > From: Radon Rosborough <radon.neon@gmail.com>
> > > Date: Sat, 2 Jun 2018 22:54:11 -0600
> > > Cc: 31692@debbugs.gnu.org
> > >
> > > > Is this in a text-mode frame or a GUI frame?
> > >
> > > It has happened in both.
> >
> > Then it's probably something specific to NS event handling.
>
> It could be worth redefining NS_KEYLOG to 1 in nsterm.m. This prints a
> whole bunch of stuff to the terminal and should let us find out where
> the key presses are being lost if it is in the NS code.
> --
> Alan Third
>
>
>
>


-- 
João Távora