realtime GI light leaking

the wall is crossed with floor, and still has leak.
i set shadows on/off, the wall still the same

i’m using 5.6.5, is 2017 or 2018 fixed this problem? i googled a lot and asked a lot people, still not getting any useful answer, so i think this is a general issue?

It says in the documentation somewhere that realtime GI direct shadows work only for direction lights now (the direct light is shadowed correctly, but the GI still thinks the shadowed area is illuminated, indirectly illuminating other stuff). Shadows of reflected lights work for any type of light (shadow of already reflected light)