Hi Stefan, Wow, this is great! I have applied your bug915103-try2.diff patch and it seems to fix the issue. Only did some rudimentary testing so far. I have patched Apache for 2hrs now and started to switch some crucial sites back to HTTP/2. Could not reproduce the problem any more. Very nice!
Thank you SOOOO much! No worries about late response. It is a great response with a great patch and I totally appreciate. For the ones that are not used to patching Apache on Debian, here's my short HOWTO (it's enough to install apache2-bin package): $ cd /usr/src/apache2-bug915103 $ apt-get source apache2 $ cd apache2-2.4.25 $ patch -p1 < ../bug915103-try2.diff $ apt-get build-dep apache2 $ dpkg-buildpackage -b $ cd ../ $ dpkg -i apache2-bin_2.4.25-3+deb9u6_amd64.deb $ systemctl restart apache2 $ echo apache2-bin hold | dpkg --set-selections Cheers, Philip