On the righthand side of the mansion, neither the roof not the pillar takes up the space above the center of the cobblestone, and a single stair block is missing.
On the lefthand side the roof "crawls" under the pillar.

The most logical-looking would be the pillar continuing downwards, meeting up with the roof (this'll require a new structure file)

Seed: 2832539179481424575
/execute in minecraft:overworld run tp @s 45337.16 131.02 -4320.05 -898.48 3.39