After light build .. still unbuilt objects + blueprint that makes unbuilt objects change for higher to lower and vice versa

After a light build I have no unbuilt objects… seems fine… then if i navigate around the level suddenly unbuilt objects appear without touching any objects… Upon further investigation i looked into a staircase blue print and noticed that if i move the staircase around the unbuilt objects sometimes raises… sometimes lowers… back and forth different numeric values for unbuilt objects… Seems like a bug… any idea what could be causing this??! Im not even sure if the 2 are related, but it seems likely…
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