How to adjust nav mesh tiles?

Anyone know how I can make the nav mesh tiles on these platforms connect? The platforms are instances of a blueprint and the player can walk on them just fine, but for some reason the nav mesh does not connect between them. Back on 4.5 or so they did connect and it was automatic. I’ve tried messing about in the RecastNavMesh object in the level (as well as the same settings in the Project Settings), but that usually just breaks everything else and at least visually never connects them. Any way to create nav mesh manually as a component in a BP? Or any other answer that would fix the issue?

BTW, what is the difference between a tile and a cell? Agents are the AI using the navigation I assume, but the other settings in there are not very clear.

FYI, I fixed the issue by adding invisible collision to the platforms. Still not sure why it didn’t do this automatically like it used to, but it works now.