This summary is not the rule. The rule text controls.
When a property is sold at a sheriff's sale, sometimes there's an older mortgage or debt on that property that ranks higher in priority than the debt of the creditor who forced the sale. If the person who bought the property at the sale doesn't pay off that higher-priority mortgage or debt, the person owed that money can still take legal action to collect it.
This means buying property at a sheriff's sale doesn't automatically wipe out older, higher-ranking debts tied to that property. The holder of that superior mortgage or lien has the right to enforce their claim using other legal procedures, which are laid out elsewhere in the law. Basically, the sale doesn't cut off the rights of someone whose mortgage or lien had priority in the first place.
For buyers, this is a warning to check what debts are attached to a property before purchasing it at a sheriff's sale. Just because the sale happened doesn't mean every debt on the property disappears. If a higher-priority mortgage remains unpaid, the buyer could still face collection efforts from that lender.