First, thanks for your answer.
No, I am not replicating the actor, but the collision position is the same. There is an actor on the server with the same collision mesh as the one on the client but in fact they do not know about each other, which is probably the problem, therefore I’m trying around a bit with replicating actor and seed but generating the mesh per running instance (Client/Server), similar to what you are describing.
That seems like a pretty good way to do it, but as you said it’s probably not suitable for what I’m doing.
Still it’s great to hear that it should work to replicate just the actor and then generate the mesh itself on the client based on the seed. I’ll reply if I get it to work 
Apart from that, do you know if it’s possible to just replicate some components and not all or better is there a similar function like AActor::IsNetRelevantFor just for components? In my earlier - obiously not so succesfull - approach all the Chunks were components that had been managed by a single actor, the “problem” now is that I can’t use that design as the components are using their actors cull distance or network relevancy and therefore either alle the chunks or no chunk at all is replicated down to the clients instead of just those who are nearby the player. I now changed all the chunks to being actors which solves that problem but I don’t like the idea of having (at maximum) 512 active actors per player in the servers level. So far that haven’t been a problem but I haven’t gotten too far in testing either.