Missing (dumping) of materials at walls/ceiling/floors

[brazen cedar]

While developing my map in editor mode, I ran into the problem that sometimes it can just reset at some walls/floors to default material. I can't understand how this happens, but maybe it can happen when I save the map, or texture it and then do something again.

The problem at first glance harmless, but it's just getting annoying that when you play some walls / floors of their material becomes default, and have to re-enter the editor and change the material, but it may also be that while you applied the material that you need, then somewhere it can again reset to the default.

I hope this problem will be solved in the future.

default material, I mean this:

[velvet ridge]

I also had this problem, it occurred when I accidentally deleted a wall, and then returned it using"ctrl + z"

In level editor it was with my textures, but when i start game it became default

[brazen cedar]

Yes, but I didn't delete any walls or use ctrl+z