Has anyone else had a model that when you have insulated some lines save the drawing and reopen it the thickness have changed. When the line that changed is selected and the insulation is removed it removes the insulation from several other lines also. We are using Windows 10 with Autocad 2018 and CADWorks 2018.

yeah, I just redraw the insulation.
FWIW I am working in mixed metric when I notice it. I wrote it off as something related to that. Same version as you.