Eric,
This typically happens when a Gtol Datum has been placed on an "&ad" dimension instead of the model driven "&d" dimension and then that dimension gets erase in the drawing. I have yet to find a solution to this issue, except to not ever use on Dim for the placement of Gtol Datums. If you are very diligent about only using show/erase dimensioning and driving your drawing dimension as the model dimension you should have better luck and not run across this again. (hopefully). I know this may not help but, the only solution that I have concluded is avoidance.
Everyone... please shed some light on this if you know anything further.
Thanks,
Michael Ohlrich, Design Engineer
Benchmade Knife Company
mohlrich@benchmade.com
(503) 655-6004 x122
www.benchmade.com