I'm having a persistent issue with my viewports in sheet layers I have set up. The files are set up as follows;
DESIGN FILE: SECTIONS
PLOT FILE: SECTIONS
The design file contains the drawn information and the plot file contains the sheet layer (plot sheet) with the design file referenced into it. I will set up my plot file correctly with my viewports referencing the relevant layers and it will appear to work for some time. After coming back to the file after a couple of day, the referenced information will of appeared to move miles out of location, meaning I need to either redefine my crop extents and drag the information back onto the sheet or simply redo the viewports from scratch. The design file isn't moving location. This can happen again and again, despite however many times I set up the viewports and don't alter the design file.
Does anyone have any idea what may be causing this to happen? I've only noticed it since updating to vectorworks 2017 and converting my drawing files to 2017. I have the 2 service packs installed as well.
Any help would be much appreciated.