The TT support person told me that IRS is considering Covid a "disaster", which the 8915-E addresses. There has been so much back-and-forth, between the CARES Act and then the June IRS policy announcement in June that it wouldn't surprise me if the IRS is still trying to figure out how to handle all this. Anyway, it remains that there is an unresolved issue within the TT calculation process - it simply does not account on the 1040 for partial rollovers of beneficiary IRA distributions. At this point I've removed the 1099-R from the software and will just wait a few weeks til the dust settles.
