The original square pillar with bricks by RobagoN has an overhang at the top that causes the outerwall layer to sag, especially at 0.3mm layer height.
The pillar on the left in the screenshot is a print of the old stl and the one on the right is my fixed stl. They are both printed at 0.3mm layer height.
I simplified the mesh in Blender so the overhang is not as pronounced. I simply deleted the vertices in the old overhang and inserted new faces to replace the old ones.