Markus Triska <triska@metalevel.at> writes:
> Please see #21722. It shows that point position after undo is different
> from what it was before, just as in this case. I constructed the case
> shown in #21722 due to the issues with undo after process output, and I
> suspect these issues are related. Redisplay may also be involved.
>
>
>> Also, how important is it to have exactly the font you mention and
>> exactly that size?  (I tried that font and that size, as well as a few
>> others, but that didn't help in my case.)
>
> The font and even window size definitely have an impact on this
> issue. Please try a different window size, and I hope you can then
> reproduce the issue, or at least #21722.

I believe the following patch fixes #21722.