Comment 12 for bug 1765353

Ok but then you'd need to add/address gnome-software, software-properties-gtk, synaptic, gnome-disk-utility, ect. as any & all of them will cause/experience the same issue, sans a segfault.

As soon as 1 app that calls a pkexec auth dialog is canceled then no other app can use pkexec auth until gnome-shell is restarted.
As mentioned this does not happen in prior version of gnome-shell.

None of the other apps 'crash', they can however get an unresponsive window or in the case of gnome-software (ubuntu-software) it'll just endlessly show installing.
There's half a dozen test cases to see this that don't involve g-c-c at all.