The gaps also have prompted a deeper, and perhaps more troubling, question: Is this the new normal?

“If this is actually a change in taxpayer behavior, long-term, and not a blip or an overcorrection,” said David J. Friedfel, the director of state studies for the Citizens Budget Commission, “then this is the new base.”

A confluence of forces made for an especially choppy and unpredictable budget in the past couple of years.

In making their predictions of shortfalls, city and state budget offices look at money from estimated tax payments that arrive during December and January, often from high earners with large investment portfolios. That two-month period is considered an “important bellwether,” according to a recent report from Moody’s Investors Service.

Many taxpayers with significant investment profits, so-called capital gains, make big payments at the end of the year. But the bad stock market at the end of 2018 meant capital losses and fewer tax payments.

It was the reverse in late 2017 and early 2018. Payments were inflated, as taxpayers navigated the new tax code. The pending changes created incentives for taxpayers to shift income and tax payments, either by waiting until the new rules took effect or to take advantage of the old system before it went away. The change in the law also spurred companies to pay out bonuses to workers, giving a temporary boost to tax revenues that will not be repeated this year.

Gov. Andrew M. Cuomo, a third-term Democrat, saw a different culprit for much of the state’s projected $2.3 billion shortfall, what he called “a diabolical, political maneuver” in the new tax rules to cap the so-called SALT deduction — something he said might be causing high earners to flee to tax havens like Florida.

“For richer people, your tax liability could have gone up now $100-, $200-, $300,000,” Mr. Cuomo said on Tuesday. “And there is a tipping point where people say, ‘I love New York, but to spend another $300,000 in taxes? I’ll move.’”