tax lien fell off credit reports-will the irs continue to attach my fed/state refunds?

I'm surprised the lien is gone, rather than just shown as satisfied.

No, once the statute for collection has expired, they can no longer offset refunds. The statute is 10 years from the date of assessment, which was shown on the notice of lien.

Really. Then there is no danger of of me complaining if it continues?

Did you hit the 10-year period of limitations on collection? That may be why the lien fell off.

Unless extended by waiver, OIC, bankruptcy, litigation, etc.

In which case it didn't expire and, unless the system broke down, the notice of lien was refiled (extended) and wouldn't drop off the credit reports.

To OP: Yes, inquire if they snatch another refund. How will you be worse off?

I'm assuming here that you don't have your copy of the lien so you can't check the statute expiration. If the notice was filed where you live now, you can always check it in the public records.