Random point in Nav Mesh spawns objects in custom static meshes (but not the default ones)?

Hi all,
Recently I’ve been experimenting with new maps for my game, and on the first one that I’ve made I have it set up to spawn the enemies in a random location in the navigable radius, however it seems to consistently spawn them inside of geometry (walls, ground, you name it). Now I set it up the same way on the Third person example map and it works fine, no spawning anywhere weird, but both in both maps you can technically navigate inside of the environment (checked using navigation view). Why is it able to spawn inside my custom static mesh but not inside the default cubes and stairs of the Example Map?
As always, any insight is massively appreciated, thanks.