> You now ask me to now invoke my title insurance
That's not how it works (at least where I live, US state of Texas). I, having bought from you, would be responsible to have my own title insurance policy. Your policy would have essentially ended when you sold the home. It protects you during your ownership. ANd my policy would protect me during my ownership. Once sold, and title transfers (whether legit or not), you as the seller have no liability (mostly, I'm sure if you committed fraud or something you could be on the hook along with other criminal issues, but my insurance is still going to pay me if I experience a loss of my purchase). So...
> "No, be that as it may, once you 'sold' the house we're off the hook; tell the guy who 'bought' it from you to contact their title insurance company"
Yes, that's exactly what they would say. It's also why it's customary for the seller to purchase the title policy for the buyer during the transaction. Although, it's a hot market the seller could have the power to deny and the buyer would have to buy their own policy.
While you owned the property at some point in time, you never experienced a loss from the title issue because you sold before the title issue was known. Your liability also ended the moment you sold the property. It's always the CURRENT owner that needs protection.