Plasma 6 overview does not show previews

When I activate the overview in plasma6 by moving my mouse to the upper corner there are no previews of the running applications. Previews are generated for task switcher and the toolbar. I know this was working at some point, so I thought I had done something in the settings, but I added a new user, logged in with plasma, and have the same problem.

Thanks in advance for any ideas. (The irony is that this feature convinced me to switch from Gnome lol…)

This appears to be a Wayland problem as the overview works normally in an X11 session.