Firesticks

Hello Today I received a tax code change notification to recover a £1900 underpayment of tax between now and the end of the tax year. I am surprised and confused, as I was under the impression the pension company used an emergency tax code when deducting tax at source, before making the final payment. Naively I thought I might actually be due some tax back! FYI: My annual income is £50,000 and the lump sum I received, after tax, was £51,000