https://bugzilla.redhat.com/show_bug.cgi?id=2061664
--- Comment #10 from vtq vtq-gnome@outlook.com --- Upstream Qt developer made patches for this issue: https://codereview.qt-project.org/c/qt/qtbase/+/445920 https://codereview.qt-project.org/c/qt/qtbase/+/447069
I tested the patches over Qt 6.4 branch (there's 5.15 cherry-pick too but it seems to be private right now). They actually fixed both Xorg and Wayland, and now the window shows up at the correct position in both cases.
When Qt versions 5.15.3 and 6.4.3 are released and arrive in Fedora this issue would be fixed. And I think this bug report can be closed, perhaps #2060988 too.