There are quite a few places where the game allows you to place things in locations that they shouldn't be like walls on ceilings without a foundation underneath. So a Curved Castle Foundation on the outside of that wall to build up would support the back walls, but the other front pieces might be breaking if nothing was underneath of them. Same goes for the stairs where that one looks like its just touching the pillar foundation, it might not be getting the foundation benefit. I will add snaps to the top lip of both steps so you can build a platform out from there for the next patch. I just increased the max height of everything in my mod a few thousand units so if there is a foundation underneath that should fix the door and battlement issue with the next patch as well.

Almost forgot, you can test the foundation issue, if there isn't one below, by adding one of my Vanilla Fence Foundation below the door on the ground and see if that keeps them from disappearing.

Ok Thank you for the fast response,Will give it a try. Funny thing is all 4 corners are built identical there is no problems with the other 3 towers, that's what was messing with me.

Ok think I found a fix for door and battlement, its been about an hour now and has not poofed yet.(fingers crossed)
here's what I did.
I used curved fluted columns all the way up.(see pic)
also cant seem to get any lights to snap to castle ceilings (full) other then the chandeliers that come in your mod any way around this?
Again thank you for your time.
http://steamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=749063283