I've been having this issue in SolidWorks 2017 drawings. I'll create the drawing and add its dimensions just fine and save. But then when I reopen the file, it shows my drawing just as it was for about two seconds before changing and dropping some dimensions or moving others. Below is an example of what's happening. As you can see the bottom right hole just goes unmarked when I reopen the drawing file. I've determined that the center mark for it is actually moving and covering the center mark of the other hole, which causes it to seem undimensioned. I've tried recreating the drawing and the part itself a couple times, both on a network drive and a local drive, but I still get the same result. Has anyone else experienced this?