Trying to figure out how to properly report the following, as both TurboTax and manual methods don't seem to give the right result.

We 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 a 457(b). We rolled the 457(b) 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 457(b) rollover should be non-taxable. When I filled out Form 8606 manually, I get $0 taxable as expected. But TurboTax puts 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 457(b). I'd like to resolve this so I can file via TurboTax. And advice / ideas appreciated!