What happens to mistakenly unreleased liens in foreclosure?

[Daniel E.]

Scenario:

First position lien from 1998 is unreleased per county records.

Property has been sold 4 times (and those owners received and released mortgages) since this time.

Most recent mortgage has a title policy showing it is in first. Court judicial report shows it is in first and does not mention the 1998 lien in any way. 

If the foreclosure sale occurs and new title is issued, what happens to the old unreleased lien?