When printing Certificates and any other docs where there are multiple recipients, the Open in Word mailmerge option shows only the first recipient. The following instructions will print for all:
INSTRUCTIONS 1
First time only - Tools > Letters and Mailings > Show Mailmerge Toolbar.
The toolbar will appear and remain on screen for future use.
Subsequently you will use this toolbar to complete the merge as follows:
INSTRUCTIONS 2
When document Open in Word at the first recipient:
Mailmerge Toolbar > Merge To Printer > OK
Then Close the doc without saving.