lightdm-webkit-greeter draw nothing in LL 2.4

[stop0x0000000a]

Hi Guys,

I am running the old 2.4 with a lot of tweaks, redecoration & etc, rather old one but works fine for me
One moment I've recently found out - I can not switch users, got black screen instead.
(right from the beginning it was configured for autologin)

So I've digged a bit:
lightdm --test-mode --debug
the same black screen.

/usr/lib/lightdm/lightdm-greeter-session /usr/bin/lightdm-webkit-greeter
same-same

ok, clean 2.4 inside VM on lightdm-webkit-greeter shows the login page.

My system

Code:

(lightdm-webkit-greeter:4935): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.40.2/./gobject/gsignal.c:2462: signal 'show-error' is invalid for instance '0xed3970' of type 'LightDMGreeter'

(lightdm-webkit-greeter:4935): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.40.2/./gobject/gsignal.c:2462: signal 'timed-login' is invalid for instance '0xed3970' of type 'LightDMGreeter'

(lightdm-webkit-greeter:4935): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.40.2/./gobject/gsignal.c:2462: signal 'quit' is invalid for instance '0xed3970' of type 'LightDMGreeter'

and nothing more. Found nothing usefull in lightdm logs.

No idea when it happened for the first time, this has been migrated a lot between different hardwares.

Is there any way to debug that lightdm-webkit-greeter?
I can try the lightdm-dtk-greeter instead but it is not LL styled

PS
i7-2600, Intell DH67BL, on-board video, SSD