I have set up a system of walls that can be destroyed. The issue I have is some walls seem to still prevent my character from going through where they were. I tested my system with a set of pillars that all destroyed ok, but now I have made them bigger they seem to still exist invisibly. I am playing in top down, the blocks destroy themselves when the character walks into a collision box connected to the block. Obviously the character has to meet a certain criteria or this would be the worst game ever 
Using 4.19.1
Does the walls spawn back in? Its better practice to use pooling instead. Also that would fix your issue. But you’ll have to do rework probably to do so. Just my opinion and not advice.
What do you mean by ‘pooling’?
Object pooling means rather then spawning and destroying actors. You recycle them and use them again. Just make set it to hidden when not in use and hide it under the map or just make it have no collision, up to you. Then when needed just un-hide it and set it to where its needed.
In games with lots of spawning this helps on performance and is just better practice. But again that is just my opinion.
Also, it sounds like the OP is getting rid of the Wall mesh, not the whole Wall instance, which leaves the other stuff, like the collision volume, still in the level.
Thanks everyone. Trial and error worked out the issue. If my wall was intercepting the ground it would not allow the player to pass over the space. When I raised the volumes to ground level it all worked. It does look like the collision box was still active after the mesh was destroyed.