bug#58135: 29.0.50; Typing getting garbled in mail-mode

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Robert Marshall <robert@capuchin.co.uk> writes:

> I'm regularly seeing what I type getting garbled when I'm typing a
> message in mail-mode. I'm not sure that it's mail mode that is
> responsible but that's where I'm doing most typing these days. At first
> I thought it was age and lack of coordination but I think that's
> unlikely.
>
> Typically I'm seeing characters not appearing and then the buffered
> text appears all at once in a randomised 'wodge'. I've just this morning typed
> Matt and ttaM appeared on the screen, I don't think I'd have pressed
> the shift key in such a wildly incorrect place.  Another example - "to
> discuss?" came out as "tsis?d oucs" (without the quotes)
>
> Typically none of *this* message came out garbled but it's a more or less daily
> event.

Is Emacs otherwise responsive to non-keyboard input during the wedge
preceeding the ``wodge''?  One way to find out is to see if a relief
appears on tool bar buttons if you move your mouse over them during that
period.

Thanks.