Purchase Order description is not populating in the description box

We have a problem with the description box on the main / general screen is not populating when a requisition is added to a document builder. This is happening when there is more than one line on the requisition.

This is the screen that it should be pulling it from

The problem that this is then causing is that the description field is then blank on the manage orders screen, see yellow line.

Does anyone know how to fix this?