Good question. I don't quite know ALL of the specifics, but these are tax deed/sale properties which:
1) can be redeemed by the former owner for a specific amount of time after the sale, AND
2) anyone with an equitable interest in the property can have the tax sale reversed/undone up to 2 years after it occurs if they can somehow prove they were NEVER notified of the sale prior to it occurring.
Below are some disclaimers/warnings directly from law firms that host the tax sales.
"All sales are without warranty of any kind. Purchasers receive a Sheriff or Constable's deed that is without warranty. Bidders should satisfy themselves concerning title and location of the property and improvements on the property including any encroachments prior to bidding. Neither our firm nor our clients can guarantee the title to any property. The tax sale is an "as is," "where is," and "buyer beware" sale. If you have any questions about specific liens or ownership of the property, you may research the title yourself or through a title company. The judgments in these cases list
the parties included in the tax suit."
"Purchasers at this tax foreclosure sale will receive an ordinary type of Sheriff’s Deed which is WITHOUT WARRANTY, express or implied. Title to property is NOT guaranteed. A policy of title insurance may be difficult to obtain."
"All successful bidders will receive a Sheriff’s Deed within approximately 30 days from the date of the sale. A Sheriff’s Deed is not a Warranty Deed."
"No Title Policy will be provided"