Many 'investors' and 'speculators' have been doing this for years. They pay extra recording 'stamps' to show a higher price than reality sometimes to get higher than reality LTV mortgage or have a stake in other properties and want to produce 'comps' that are not based in reality. Sometimes the real estate agents are in on it, and sometimes not.
Avoid using any sales like this. If you MUST use a sale like this, use the MLS sale price stating that it was verified as the true sale price by the Realtor. Explain that the sale price as listed in the public records appears to be wrong and that you are using what you believe to be correct.
Report any sales you find like this at the Mortgage Fraud Watch List .org so that many of the mortgage fraud investigators, law enforcement, regulators, and lenders fraud departements will find it and hopefully do something about it.