This can be also reproduced by running "dm-tool switch-to-greeter", so it is in fact an issue in the lightdm-gtk-greeter code or in lightdm. The greeter queries lightdm several times to get the status of the lock hint, which is not set when switching to the greeter (SwitchToGreeter).
The following patch for lightdm-gtk-greeter removes these calls:
This can be also reproduced by running "dm-tool switch-to-greeter", so it is in fact an issue in the lightdm-gtk-greeter code or in lightdm. The greeter queries lightdm several times to get the status of the lock hint, which is not set when switching to the greeter (SwitchToGreeter).
The following patch for lightdm-gtk-greeter removes these calls:
http:// pastebin. ca/2520577
However, setting the lock hint might be the better and cleaner solution, because the user session actually gets locked in this scenario.