Please also try uninstalling (don't just turn them off) these extensions:
'<email address hidden>' '<email address hidden>' '<email address hidden>' '<email address hidden>'
Then reboot. Does the problem still occur?
We need to try this because extensions cause a large number of bugs in gnome-shell and the lock screen is part of gnome-shell.
Please also try uninstalling (don't just turn them off) these extensions:
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
Then reboot. Does the problem still occur?
We need to try this because extensions cause a large number of bugs in gnome-shell and the lock screen is part of gnome-shell.