Level Streaming creates seams in procedural mesh

Oh… And I´m working on 4.24

Hey there… So my Goal is to create an endless self generating open World using procedural meshes in sublevels that are arranged in a grid. It does work fine so far but the problem is that, although the tiling seems correct, there are visual noticeable seams dividing those chunks I created. I already tried combineing them all into one single mesh, but the problem remains the same… Is this an engine-problem or am I just missing out on something?

Here is a picture of what is going wrong: