I’m experiencing an issue very much like the one described here: Actor not completely destroyed on Destroyed? - World Creation - Epic Developer Community Forums.
I have enemy pawns hitting a defensive wall and both the pawn and the wall are destroyed. However, the next enemy pawn to reach that space - which should be empty now - stops moving right there as if obstructed. I did the console pxvis collision thing suggested in the post and nothing is visibly in the way. Prior to putting the walls in the game, the pawns moved through that space with no problem.