Hard to know as we can't know all the details of your situation.
One thing it could be? IF you have children/dependents, the Advanced Child Tax Credit was only for 2021 (so far), and the refund could be due to those extra credits...BUT those credit $$ aren't included in guesstimates for next year's taxes...and if everything else remains the same, you might owe over $1000 next year....based on everything else being the same for 2022.
IF you don't believe you really need the Estimated forms, you could ignore them since the IRS and State do not know they even exist...or perhaps, increase your paycheck withholding at work to make up for any guesstimated/possible shortfall for 2022.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
