Some Contact Print Mailing Labels With No Names

I was able to reproduce this on the Demo site.

http://drupal.demo.civicrm.org/civicrm/group/search?reset=1&force=1&context=smog&gid=3

<b>Print Mailing Labels</b>, and you will see that <b>Pavel Bursna</b> doesn't prints <b>no name</b> in the mailing label PDF, although his address is included.

One some of my client sites, this problem seems quite severe, as many as 90% of the contacts, on other client sites the problem is almost non-existant.

Pavel Bursna is the only contact on the Demo site with this issue that I can find, but you are welcome to contact me for logins to some of my client sites for debugging purposes.