i made a new post more detailed
that’s the missing texture texture, you see that when you don’t have the texture
rp_downtown_v2 probably has a lot of custom textures not packed within the map, and you probably just downloaded the map from a server instead of garrysmod.org where the download would have the textures
well i was playing on the map 5 hours before i have css and all half lifes and it was fine before
Did you Alt+Tab out of your game at all? Usually that can cause some texture errors.