It is possible if several seats were empty, or players were sitting out. That would mean few hands per orbit. If there were only 3 players at the table, that would be about 17 opportunities.
If you continue to have problems please zip up and email the problem hand histories with details of the issue you are experiencing or a link to the relevant thread and send it to hm2support@holdemmanager.com
All original hands that are auto-imported get moved to an archive for performance reasons. Your \HM2Archive is in C:\HM2Archive by default, but you may have put it anywhere. The archive should be organized by \Month\DayOfMonth e.g C:\HM2Archive\2009\07\31 or if it was auto-imported with v7283+ it would be in C:\HM2Archive\SiteName\YYYY\MM\DD.
When sending any hand history files please zip them (right-click > send to > compressed folder) before attaching them to an email. If the attachment is too big to attach to an email please upload them to a file hosting site like dropbox or filedropper and send us the download link.