I suspect this is a problem with my friend's (friend B) computer. However, everything loads fine except for the walls when we play.

Friend A and myself have played a few games with no problem. Friend A's computer is several years old and sometimes chugs with TTS, but everything loads fine.

Friend B recently bought a new computer (I don't know the specs) and, while everything else runs smooth, the walls of our maps do not load for him.

I get this is a long shot...just looking to see if others have had similar problems and what solutions they have. Again, it works for myself and Friend A so I don't think it's a map issue.