There has been a slicer bug in Z-suite since v1.12 and newer version, including Z-suite v2.x
Does every material give you such results? Is the problem present in every layer thickness?
Are you able to send me the .zcode files where the problem seems to appear?
Please contact me via PM, I would like to investigate the issue fully and I need some additional information.
This would be very easy to see if ZSuite allowed us to preview the build at not just a percentage or layer but at each step within a layer like other software on the market does. (Hint....hint)
If you click the % symbol at the top of the slider you can change it to pieces(layer) increments only in suite 2 though as far as I am aware.