As I've argued, Libertarianism doesn't work if third parties are free to ignore the consequences of other people's contracts. (The only reason I can't steal your TV from you is because I am not free to ignore the right to that TV that you acquired from that contract. If I was free to ignore that contract on the grounds that I wasn't a party to it, you would have no recourse against me when I stole your TV. I would not be required to accept that it was yours.)
That's only true if you refuse to separate the concept of ownership from the contract that assigns it. As I see it, it's none of my concern
how you came to own that TV -- what matters is that you own it now. The TV is not a bitcoin that needs to prove its lineage to everyone who comes across it, and the sales contract is not a passport that you need to carry around to prove you own the TV. A third party can't ignore the contract and pretend you don't own the TV any more than he can ignore a contract with your barber and pretend your hair hasn't been cut.