‘Remove default margins’ in contextual spacing prevents gap between items in masonry gallery
Hi Illarion,
Thanks so much for your report!
This is somewhat to be expected, since you deliberately decide to set the margin for every li to 0.
Furthermore, it is actually unnecessary to set the margin for li’s to 0 because they have no margin by default 
If you still want to do this, you can use the following selector instead of the general li:
li:not(.bricks-layout-item)
Best regards,
timmse