This document describes an inconsistency in how PDM maps attributes to the PRPSHEET block and how it maps to the Custom Property block.
Mapping variables to the PRPSHEET section of drawings is not intuitive.
Example: your variable is “Number” and points to a custom property Num:
If you have a mapping to only PRPSHEET on Num for slddrw, you will not get anything from the model unless you have manually created a Custom Property in the model called Num.
If you have a mapping to PRPSHEET for the drawing and Custom Properties for only the model (or you manually create the Custom Property in the model), then as long as the PDM add-in is turned on in SolidWorks it will copy the value from the model and put it in the Custom Properties of the drawing. But it will not fill in the variable on the data card.
Instead, have a mapping to PRPSHEET for the drawing and Custom Properties of the model and the drawing. Now it will carry the value over from the model into the custom properties of the drawing and that will carry over to the variable in the datacard for the drawing.