I confess I'm having trouble with the exact issue but let me take a stab....
We have a crappy system in Pennsylvania for collecting taxes, both current year and delinquent years. It's pretty darn hard to verify what's been paid and who collects it. The really crappy thing is that even when you find the correct tax collecting authority, they won't back their certifications.
So, when the tax certification contains errors, the homeowner must pay.
If the error is covered by title insurance, the insured is covered and the title insurer may go after the previous owner for the tax.
Each case is decided based on the facts of the case.
Not sure if that helps, but I hope so.