Desktop Grid + and - signs do not disappear

My problem is the following: I am using up-to-date Tumbleweed with KDE and I turned on the Desktop Grid effect. When I press the shortcut, the grid appears and when I select one of the desktops, the desktop is opened, but the + and - signs to add the “new desktop” stay.

That’s a known bug but should be fixed in KWin 5.4.1.