Once again, please send a printscreen of your inkscape document with the document properties tab open. If you're using windows 10, I might just have a solution to your problem.
Since we are trying to trace the problem down, we can experiment, try to find out more about it.
Try to set the "X" and "Y" boxes some values, like 2000. Also, a screenshot of your entire inkscape document with all of the document properties tab open could help