Whatever property taxes you paid in 2019, are deductible on the 2019 tax return. TO a point, it does not matter what year you paid *for*.
Whatever property taxes yo upaid in 2020 are deductible on the 2020 tax return. To a point, it does not matter what year you paid *for*.
It is not common for property tax payments to be for a calendar year. For example, my yearly taxes are due every Nov 1st. It pays taxes for the period from Nov 1st, through Oct 31st of the next year. But I deduct those taxes as a rental expense in the tax year I "actually" pay it, regardless of the fact the period crosses the calendar year.
