Bizarre problems with the polyprinters

I had some bizarre problems with the polyprinters that I think are actually slicer issues. Its like they kept printing layers without incrementing the Z axis. The nozzle was plowing though globs of plastic. This happened with two different printers and three (related) designs. Kisslicer doesn’t complain about the STLs and the look good in a few different viewers. Any idea what I’m doing wrong?