Qt6-base 6.7.x has a bug that crashes polkit-kde-agent (null pointer)

Some of us have had problems with KDE apps that used to request the root passwd for, e.g., saving fstab in /etc or mounting a drive in dolphin. It turns out that qt6-base 6.7.x has a bug that crashes polkit-kde-agent (null pointer). Restarting /usr/lib/polkit-kde-authentication-agent-1 restores the window requesting the root pw, but it needs restarting each time.
Test case:
Open /etc/fstab in kate, add a comment, press ctrl-s to save. You’ll see an error message that you don’t have permission to save the file. What should happen is a pop-up window requesting the password for sudo. After killing and restarting polkit-kde-authentication-agent-1, pressing ctrl-s pops up the authentication dialog and saves the file correctly. Trying the same thing w/o restarting the agent gives the same error. If you run /usr/lib/polkit-kde-authentication-agent-1 in a terminal, the crash and null pointer error messages appear.

Cannot reproduce (currently on Unstable with qt6-base 6.7.0-3).

Do you have a link to an open bug or something?