unsecured supplemental

Is the winning bidder responsible for paying unsecured supplemental property taxes in additon to the secured taxes?

Supplemental taxes are property taxes due based on a reassessment of the tax rate in a specific tax year. Supplemental property taxes are preliens just like the regular property taxes and will be super senior to any loan. Whenever you have a preliminary title report issued by a title company the first 2 items on the exceptions page are always the property taxes and the supplemental taxes.
If you are looking at an unsecured tax lien then that lien would be prioritized by the filing date of the lien.