The StartTransientUnit (fka. "run0") support of COCKPIT-1363 introduced in PR#22373 uncovered several bugs and race conditions in our polkit integration and systemd_ctypes. These are particularly painful with polkit 127's socket activation in debian-testing and arch, but in principle happen everywhere. These bugs already exist on main, but are just not exercised enough in our tests to notice them.

https://github.com/cockpit-project/cockpit/pull/22373#issuecomment-3760110147 ff. has lots of debugging notices.

rhn-engineering-mpitt has an initial systemd_ctypes fix and an initial cockpit PR which fixes this, but this needs to be investigated/cleaned up properly.