Jeff nothing scientific here with ACIS v21 to v2018, just what I observed on screen after trying to overcome my original problem which is now fixed with a workaround for now. The original problem was unselecting a v2018 acis object ( still occurring ), so I tried v21 instead which was ok. So in v21 I then considered converting the acis solid to a surface ( to save on file size ) and the resulting surface object had some lines between the original extruded text after conversion, which I wasnt happy with after rendering. I tried the same method in v2018 and the lines where visibly worse, so I discontinued this approach altogether.
Jeff what I did in this method was most likely going against the grain so to speak but it was just an attempt to solve a problem that no other person has experienced at all in v2018pp. I was just seeking a workaround to the original problem that led me to try alternate methods, most likely a crappy idea though.
TCW V21, 2016-2018 PP, Animation Lab V5, TurboPDF V2-V3 & LightWorks Rendering Engine mostly.