I'm not sure what LightDM issue you're referring to, but I do believe similar issues with gnome-settings-daemon dying at any time will cause a loss of the theme.
However I have tried to be careful to distinguish between different error codes because there could be multiple bugs. In my case, if the theme is missing when I log in then .xsession-errors always shows that gnome-settings-daemon had the codes:
"error_code 8 request_code 3 minor_code 0"
I'm not sure what LightDM issue you're referring to, but I do believe similar issues with gnome-settings- daemon dying at any time will cause a loss of the theme.
However I have tried to be careful to distinguish between different error codes because there could be multiple bugs. In my case, if the theme is missing when I log in then .xsession-errors always shows that gnome-settings- daemon had the codes:
"error_code 8 request_code 3 minor_code 0"