Should I check the box that an IRA rolled over from a deceased person's IRA is inherited?

[Son-in-the-NW]

Deceased dad's IRA was rolled over into a new IRA for mom (spouse).  Dad had taken a portion of 2018 RMD.  Balance of Dad's 2018 RMD was withdrawn from mom's new IRA. Received two 1099Rs. Turbotax asked if mom's IRA was inherited, and I checked "yes".  Turbotax is showing mom's regular distribution (which is part of dad's 2018 RMD obligation) as non-taxable and shows "Rollover" as the reason on the 1040. Seems like regular distribution from Mom's IRA should be taxable. 2b shows "taxable amount not determined". Distribution code 7 is checked on mom's 1099R. 

[macuser_22 · Accepted solution]

If the inherited IRA was rolled into your mom's own IRA and the 1099-R distribution code is 7 then it is no longer an inherited IRA - it is her IRA.

If the box 1 and box 2a amounts are the same and the box 2b (not determined) is checked then, assuming that the IRA/SEP/SIMPLE box is checked, it should all be taxable on the 1040 line 4b.