Their letter states"We changed your 2020 form 1040SR to match our record of your estimate tax payments, credits applied from another tax year, and/or payments received with an extension to file. As a result, you are due a refund of $127.41", which is what I received.
Turbotax advised I was due a refund of. $1200 and filed that return for me electronically.
IRS added no further explanation.
