It seems like it only happens when I finish one scene, or part of a scene, then change to a new place in the time line to render, or a new scene. As in, it won't be rendering a scene and then suddenly drop textures in the middle of a render. I think it's just when I start a new batch render after previously doing one, but I'm not positive about that.
My only thought is that the textures are on the server, and the computer I'm on has lost it's connection to the server some how, so while it can open the scene which is also on the server, it isn't getting the textures any more maybe? It does sometimes loose connection to the server, but then I can't even open that directory, so it would seem odd that I could get to the folder to open the Maya file, but then the textures don't load. And even when it's lost the connection to the server, it's been rendering the scene right with textures and everything, so I'm not sure that idea makes any sense.
Anyway, I'm just curious if anybody else has any insight on this. I couldn't find any good words to search for to find any additional info on this, so if anybody knows how to prevent this without constantly restarting, that'd be great.