Dimensions flying off the layout?

Why do dimensions that I have placed on the layout decide to fly off the item dimensioned or even the outside layout?
I mark up a whole layout, and then come back to it a bit later (1 hour - 2 days) and it occurs??
I trust there might be a simple fix out there?
Piet Boer

Hello - can you please run the Rhino command SystemInfo and copy/paste the output here?