Copied/pasted assets invisible hump?

[WALP]

First of all confirm whether the issue is related to the assets or the way you set the level up, by adding the assets to another level and seeing if the issue persists.

level editor does not show everything the individual assets contains.

in in-game debug menu I believe there is an option to see the whole world in wireframe or something, which should let you see invisible stuff like bodies and geometri, though I am not exactly sure what is called.

if this does not help you locate the source of the problem, You could try opening the assets in the model editor to confirm there are no invisible bodies that may be causing trouble.

Finally there is also the possibility of the mesh(model) itself being the problem, so you may want to import it into a 3rd party software like blender or maya to check for weird geometri that might be causing problems.