GDM hard freeze while hovering over menu elements (Session cogwheel or quick settings) after mr2777

Have GNOME 45alpha tag from FCGU Arch repo, only mutter from main.

Laptop, single display.

GDM hard freeze while hovering over menu elements (Session cogwheel or quick settings menus) after !2777 (merged)

Bisecting leads to this e52641c4 as a 'bad' commit.