Ok, so you are simply spawning the actor, but not modifying the Edge Array? If the edge array is not modified spawning a tile does nothing. If you are using one of the older versions of the toolkit where the edge array is not a nested array this is as simple as setting the value of Edge Array at the appropriate index to 0,0,0,0,0,0,0,0. For the newest version (which Epic told me they would upload this week) with nested arrays this is quite a bit more complicated, as edges are only one-directional, meaning you need to modify the edges of all tiles that are connected to the spawned tile index. Because this is more tricky I have created a Spawn Tile function that does this for you, which is located in the Utility section of the functions of BP_Grid_Manager (only in version 1.5)