Built House Reverts To Blueprints Merged

I was wanting to expand my dwelling around the same time I got the Tudor tileset. So I attatched Tudor foundations to my existing dwelling, and while crafting bricks I popped through a portal to do something. Upon my return the existing crude wood dwelling was now just a blueprint. Existing items in the dwelling were unaffected.

To rectify this I added the material for 1 new foundation piece after removing the other new pieces, the dwelling became solid. Relief. Said Tudor foundation was then removed.

To confirm this was happening as I thought I then added a single Desert foundation blueprint and popped through a portal and back. Same result. Same fix.