Building Vanishing! (not an LOD problem)

Hi, i am trying to make a player house (more like a mansion) on the throat of the world. I have the exterior of the mansion looking good, except the main mansion building just disappears in game, as if i never placed it in the CK. The mansions patio, all the trees, and everything else i placed on the exterior of the mansion is still there. but its just like the mansion disappeared, you cant see it, and there is no collision or anything. Sometimes or rare occasions it will show up and be fine, but this is only after i re-save the mod in the CK and load my game at the mansion. if i fast travel to Whiterun or any other place and fast travel back to the mansion (the mansion has it own quick travel point), then it happens and it is just gone. If you think it is necessary, i can post some pictures of what it looks like in the CK and what happens in game also. Anyway does anybody have any idea's on what could be going wrong?
P.S The building i am using for the mansion is the exterior castle building found in Windhelm, it is also the building that has the 2 doors that you go through to see Ulfric Stormcloak. It's name in the CK is WHpalace1.

It's not just you. I got a little farm house near Whiterun, (a copy of Gerdur's house in Riverwood) The house disappears all the time, but the door sits there in mid air. It has to be a bug in the CK. Going inside and back out a couple times should make it show up. But when I leave Whiterun, it's always there. I don't know if there's a fix for it though.

well one time Adriannes shop disapear i went crazy, well it was solved by a reload but still , crazy stuff