looking at 2nd lien foreclosures- don't see any in 1st position?

decided to do some more research on these and found several that do not have a 1st listed on the profile. what does this mean?

We use a computer model to determine lien position. This is why we encourage you to read the Disclaimer. If the computer model cannot determine the lien position it will usually show a ? in the lien position column. It is unusual that you would see a 2nd without a 1st. If you want to send the radar ID# to support@foreclosureradar.com the support team would be happy to look into that for you.