Notification system is not using the GTK dialog

Hello everyone, I’m using Pop!_OS 21.10 and my notification system is not using the GTK dialog provided by GNOME, independently of the origin (browser, system, apps…).

IDK exactly when this issue started, because I generally disable all notifications. I’ve just noticed yesterday.

Three days ago, I’ve tried i3wm but came back to Cosmic/Gnome session. The design looks similar to i3. Here is a screenshot.


Did you check out, if other people on this operatings system experience the same issue, as you do?