They are more likely to get overturned and pierced in a court of law generally speaking.     

I would imagine there is a way to remove someone "in abstencia", you can get a divorce, overturn custody, and adopt even without all parties involved if you can prove that a valid attempt was made so I would imagine there may be a way to clear title as well maybe not within 12 days but we'll see.

Since the sale could be overturned apparently, no one will likely pay you any premium until the one year is up.

Manhattan Beach just overturned their ban on strs & Hermosa Beach is pretty clear on their policies. 

With so many overturned sales these days, it's actually a known risk and not even that rare.

I have not seen a cert of title overturned by the owner during that window but have seen a case where the attorney representing the lender failed to show up at the auction to set the openinng bid and the property went for peanuts.

She failed to respond to the notice of review from CMHA to file an appeal to fight the rent increase so the decision could not be overturned. 

It took the state a year to overturn the ride-share fingerprint ordinance Austin enacted.

If not it likely can be overturned for lack of consideration.Did the attorney representing the LLC inform you that they only represented the LLC? 

Almost every PA court case overturning a tax sale is overturned on bad notice.In one case I researched, the judge overturned the case, because notice was sent to "Smith Debbie", and it should have been either "Debbie Smith" or "Smith, Debbie".Effectively there is not time limit on an appeal, only a time limit on the appeal AFTER the former owner finds out about the sale.