I've done some very basic modelling in hex and came across this in my first project, i found it seemed to do this on large polygons, adding more by tessalation tool seemed to reduce/eliminate this.

Im not sure why it does this on some and not others, maybe its only on one side of the column and it is happening on the others but its out of view as they may be turned 90/180 degrees?

Maybe someone with more modelling experience can help more, might be an idea just to add a comment in the details box on your download to turn off "smooth polygon" option when rendering in poser. :)

Tools:- Win10, Dell XPS8900, ZBrush, Marvelous Designer 11, Hex 2, PSP8. PSP 2019 Ultimate, DAZ Studio, Affinity Photo, Affinity Designer, Filterforge 11, flowscape,  Classic UVMapper, and several headache tablets.