It seems that if Ubuntu 24.04 VM is launched on R6725 host, it will fail for timeout. This is visible with RTA as well as COIN. 

For example : https://coin-for-jenkins.ci.qt.io/coin/api/log/qtqa/tqtc-qt-rta/e7b2807702567d9c74b994b7d73fbb7dfeb297ef/LinuxUbuntu_24_04x86_64LinuxUbuntu_24_04x86_64GCCqtci-linux-Ubuntu-24.04-x86_64-50-d66d95UseLegacyInstructions/bbcd683d9f3039330b5a719fd58674f881e9e6c6/1753176312/jenkins_1753176313/log.txt.gz

https://coin-for-jenkins.ci.qt.io/coin/api/log/qtqa/tqtc-qt-rta/e7b2807702567d9c74b994b7d73fbb7dfeb297ef/LinuxUbuntu_24_04x86_64LinuxUbuntu_24_04x86_64GCCqtci-linux-Ubuntu-24.04-x86_64-50-d66d95UseLegacyInstructions/bbcd683d9f3039330b5a719fd58674f881e9e6c6/1753176308/jenkins_1753176309/log.txt.gz

And

https://testresults.qt.io/coin/api/log/pyside/pyside-setup/fdc83c8c8d7c901546e2880459549d067845d0ec/LinuxUbuntu_24_04x86_64LinuxUbuntu_24_04x86_64GCCqtci-linux-Ubuntu-24.04-x86_64-50-9472a4Sccache_UseConfigure/53e7a0a31897372439253854de2f774c590a96b6/build_1751537878/log.txt.gz

in last log, one can see that it fails 11 times on same spot, when running on R6725 host. Only when VM is started on 640 host it will go forward.

Also it seems that it really affects only Ubuntu 24.04. I haven't seen other Linux distro or Win  failing on it.