Grid view on screen edge is borked.
It’s supposed to be part of “Overview” now, but you can only select “Overview” on screen edge, which as far as I can tell is completely redundant with “present windows”.
The effect exists under Meta+G, I just can’t bind it to screen edge.
edit: https://bugs.kde.org/show_bug.cgi?id=478137
edit: and that’s why you wait a few point releases before switching 
Fortunately I anticipated this and didn’t update my main system, only my spare laptop, for testing purposes.