My wife & I make purely non-deductible contributions to trad IRAs, and then convert to Roth IRAs. As result, we generally have a total IRA value of $0 at the end of each year.

In 2016, a former employer (govt) required my wife to rollover money from a 401(a). We rolled the 401(a) it into her traditional IRA, but this occurred after we had done our annual trad IRA to Roth IRA conversion. So, unlike all other years, she ended up with a balance in her traditional IRA at the end of 2016.

I'm not expecting to owe any tax - all IRA contributions have been non-deductible and the 401(a) direct rollover should be non-taxable. When I filled out Form 8606 manually, I get $0 taxable as expected. But TurboTax and TaxAct put a taxable amount in 1040 line 15b, no matter what I've tried, including manually adjusting the trad IRA basis for the amount rolled over from the 401(a). And advice / ideas appreciated!