Custom Row shapes overlay issue

Hello Everyone! I Have been a user almost since day one and I’m loving the plugin so far.
I have an issue regarding the custom row shapes.
When I try to populate rows with full height objects (or if i try to overlap a row with a module on the bottom using negative margins) the custom shape overlays the object: is it as intended? Am I missing something?

I tried to fiddle with z-index to no avail: any help will be appreciated!

here is a picture