Emacs 26.3 GTK Errors (gnome)

[zaxmyth]

I updated my testing branch this morning and am now seeing the following when launching emacs:

$ emacs --no-init-file

(emacs:3550): Gtk-CRITICAL **: 07:52:04.599: _gtk_css_image_get_concrete_size: assertion 'default_width > 0' failed

(emacs:3550): Gtk-CRITICAL **: 07:52:04.600: _gtk_css_image_get_surface: assertion 'surface_height > 0' failed

(emacs:3550): Gtk-CRITICAL **: 07:52:04.600: _gtk_css_image_get_concrete_size: assertion 'default_width > 0' failed

(emacs:3550): Gtk-CRITICAL **: 07:52:04.600: _gtk_css_image_get_surface: assertion 'surface_height > 0' failed

(emacs:3550): Gtk-CRITICAL **: 07:52:04.600: _gtk_css_image_get_concrete_size: assertion 'default_width > 0' failed

(emacs:3550): Gtk-CRITICAL **: 07:52:04.600: _gtk_css_image_get_surface: assertion 'surface_height > 0' failed

When running emacs in daemon mode as a service, emacsclient is unable to receive stdin.

[AgentS]

I don't know if this is relevant, but recently gtk3-classic was dropped from repos.
If you had it installed, check it's status (replace with gtk3 or update from AUR).