Same here, on the Gnome shell, I was using Numix theme, but after the update First the image on the login screen has changed.
And the Numix theme was broken, it was trying to use either adapta-breath or arc maca instead. context menu on the desktop, as well as shell-pop ups, like calendar, were broken.
However when I changed the theme it seems working.
Also, I noticed that for last 2 updates pamac fails to see that there are new updates.
At the first time, it seems was the problem with the mirror, thus I manually changed it to
## Country : Germany Server = https://mirror.netzspielplatz.de/manjaro/packages/stable/$repo/$arch
but today also, it failed to see the updates, but work flawlessly via terminal.
P.S. I am not using the update notifier extension, rather I was going to the update section in the pamac