Sometimes (okay, once, but I'm told it happens sometimes), I'll open a drawing and the number in the titleblock is wrong all of a sudden.  I did the redlines yesterday and linked the drawing number field in the titleblock to the DWG NO. field in the datacard.  I saved it and checked it in.

When I opened it today, the drawing number was flat wrong.  I have no idea where that new number originated (but I'm new here), nor why it would override the linked field.

What's the deal?