Is your Trace Reference turned on in images 1 and 3? Can you upload those again without the Trace? It is pretty hard to discern the lines with it turned on.
Could you also turn off the layers of any other elements and lines (like Structural Grid lines etc.) so we can see only the elements that need to properly intersect.
Could you also do that you place texts at each skin of the problematic connections and type in the text the Intersection Priority Number of the Building Materials assigned to each skin?
By the way, whatever you did in image 2 was getting you closer to the solution as the connections seem cleaner.
One thing I am thinking about is that you cloud try assigning a higher Intersection Priority Number to the Building Material of the plaster skin (this applies to the leftmost problematic connection of image 2). That may clean up that connection.
I think there can be cases for such connections that will not resolve properly, but the ones you are showing you should be able to set up so they join properly.
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