While the distribution is not taxable, Roth IRAs inherited by a non-spouse beneficiary are always subject to either annual RMDs based on life-expectancy or to complete distribution by the end of the 5th year following the year of the Roth IRA owner's death under the 5-year rule.
Since you are taking beneficiary RMDs based on your life-expectancy in the year following the year of your mother's death, reduced by 1 for each subsequent year, you need to make the late 2018 RMD and then file 2018 Form 5329 Part IX requesting waiver of the 50% excess accumulation penalty. The distribution itself will be reportable on your 2019 tax return along with your 2019 RMD from this account.
If you have no 2018 Forms 1099-R that would cause 2018 TurboTax to ask if you received all of your RMD for 2018, since you appear to be using the CD/download version of TurboTax you'll find it easiest to prepare Form 5329 Part IX in Forms mode:
- Enter on line 52 the total amount of RMDs you were required to take for 2018.
- Enter on line 53 the amount you actually took ($0 if you had no other RMDs),
- Enter on line A of the Waiver of Tax Smart Worksheet the amount that you received late and on which you are requesting a waiver of the penalty (the difference between lines 52 and 53).
- Finally, click the Explain button and provide an explanation of reasonable cause for taking the RMD late (financial advisor provided incorrect information regarding the requirement to take an RMD).
- TurboTax will complete lines 54 and 55.
Immediately prior to filing, double-check the printed Form 5329 to make sure that TurboTax has not removed these entries. (Under some conditions TurboTax will remove these entries if you click the Continue button on the Your 1099-R Entries page anytime after making these entries in forms mode.)
