I am noticing the same issue.
I have Post Tax 401(k) Contributions rolled over to a Roth IRA (with some appreciation).
All the distributions went into a single Roth IRA account.
Turbotax is doubing the amount on Form 1040 Line 5b.
my guess - it is adding both the Taxable amount from 1099-R Box 2a and the difference between Gross Distribution 1099-R Box 1 and Employee contributions 1099-R Box 5.
Please advice on a way to work around this.
edit: I intentionally skipped entering 1099-R Box 2a, and the form 1040 Line 5b now shows the correct amount with label "ROLLOVER".
