Sometimes when i trigger either one of the mentioned actions i am not able to 'untrigger' it. e.g. when i want to show the desktop grid my configured keyboard shortcut works just fine and does just that. However, the same shortcut doesn't always get me back to my desktop. Escape doesn't work either. I then have to reach for the mouse to click one desktop to get out of the desktop grid view. This leads to a huge interrupt in workflow. I do use custom configured shortcuts.
*** This bug has been marked as a duplicate of bug 360841 ***
Temporary solution thanks to Thomas Lübking. Try running "kwin_x11 --replace &" After that, shortcuts should work again.