Okay, I got it working. 
Operator error. 
The problem was that I was making metadata changes in lightroom which I did not save to the file.

Sorry for the false alarm.
Qimage is a great product!
I use it for all my printing.
Thank you for what you do and for your support.

Unfortunately the video you reference does not cover adding a metadata field to LR that is not already there.  The 'IPTC Caption' field is not included among the fields that I can use within LR, and the 'Caption' field that LR does offer does not print in Qimage.  So I am still left with no solution to printing captions in Qimage. 

In Lightroom Classic, 'Caption' appears in the Basic Info section.  There is no 'Caption' nor 'Description' field in the IPTC sections. So I used the former.  In Qimage only 'IPTC Caption' is offered.  Is that the problem? I cannot see how to add 'IPTC Caption' or 'IPTC Description' to Lightroom.

 I am unable to print metadata Captions under my photos. In Edit Page, I bring up Add Floating Text and choose Advanced. I enter $D, but the Caption does not print.  All the other option codes work fine. What am I doing wrong?