Oh... I also discovered an additional message in the wireshark dump.
Tomcat replied with a goaway packet with the text:
Connection [22], Stream [19], An error occurred during processing that was
fatal to the connection
> -Ursprüngliche Nachricht-
> Von: Thomas Hoffmann (Speed4Trade GmbH
Hello Mark,
I did some further investigations. I hope I don’t bother you with this topic.
I was trying to narrow down the tomcat version where the problem started to
appear.
The problem with the interrupted connection started with 10.0.0-M8
With Tomcat 10.0.0-M7 everything works fine.
Comparing