Fluid obstacle (fluid doesn't move smoothly)

How do I fix these sharp edges, it’s like the fluid hits that invisible part of object (like a stair) and then moves on.
It doesn’t matter the domain bake size neither the amount of faces the obstacle object has.

It might have something to do with the model being a single plane(not having any thickness)? I would not know, really, but that is what people usually say.

I have a similar issue - in my case the fluid penetrates the thin walls during splash regardless of whether I use only the walls of the object or add a different, thicker mesh. fluid resolution is at 200 already, I don’t think I want to go too high on that unless that is the only way (whereupon I would like to ask what should be used).