Skyrim HiRes Texture pack for steam problem

[skyrim781]

Well i was playing skyrim and was doing the thieve's guild questline i broke into the meadery through the sewer and then i started walking and both ways i went left and right there was this almost orange fog everywhere where all the textures should've been i really dont know why this is happening it doesnt happen anywhere else just there so i shut the mod off and sure enough that fixed it. I downloaded it on steam and it is an official mod so why would've it been having this problem