It's only taxable if you both itemized and did not take the full salt deduction at the same time (kind of hard to do, not impossible). I think I read it's like 0.2% of taxpayers. Show your tax person your federal taxes from last year and ask if that applies to you.

https://www.irs.gov/newsroom/irs-issues-guidance-on-state-tax-payments-to-help-taxpayers