Why 1099-R shows amount on box 2a as taxable income? as I have roll over all money to another custodian. (Spouse death - work distribution to my name) ?

Spouse passed away in 2021 - I was beneficiary for her profit sharing, (stock) requested to transfer to me all and I roll over to another custodian.  her work HR issued 1099-B and 1099-R,  since I have roll over all money why 1099-R shows some taxable amount?