Origin/Destination arrows issue with book_tag variable in formula

Hello,

I am having an issue with Origin/Destination arrows in solidworks electrical.

In the project properties, I have given the arrows this formula; BOOK_TAG + "-" + FILE_TAG

However on the drawing, the BOOK_TAG variable appears on the arrows as blank. The BOOK_TAG variable IS working in other formulas for other symbols. Why does it not work for the arrows? Is this a bug?

Here is a screenshot where you can see the 'blank' BOOK_TAG variable

Also, I would like to the origin/destination arrows to reference the components they are connected to. For instance, the top arrow, if complete, should say X11512-01-03 XK5-01.

Any help with this would be appreciated.

Thanks!

SolidworksElectrical