UTF8 incompatibility between LaTeX files GNU Emacs and Xemacs

Hello


I am not sure who is the culprit.
Here is the scenario:

I use Xemacs 21.5.34 Mule -vanilla

And

GNU emacs 24.5 or 25.0.50 -Q

I open with Xemacs a latex file, using
auctex, modify it, save it using   UTF8 encoding.

GNU emacs does not display this file correctly. I screenshot
is attached.

The other way around it works, also latin-1 is not a problem.

Any comments?

Uwe Brauer