Issues with Taxable Amount for an After-Tax 401K to ROTH IRA rollover

[megabackdoorissue]

Hi, I'm running into an issue where TurboTax seems to be incorrectly recalculating my Taxable Amount for a rollover from an After-tax 401K into a ROTH IRA. Using sample numbers for the 2024 1099R to describe the situation:
Gross Distribution: $40k

Taxable Amount: $0

Employee Contributions: $35k

Code: G

TurboTax calculates a taxable amount of $5k, but I had an additional $10k of contributions in 2023 that were rolled over. Hence, the $0 taxable.

What's the correct way to reconcile this?

[DanaB27]

To clarify, are you saying you had more than $35k after-tax contributions in the 401(k)? If yes then you should contact the plan administrator to correct the entry in box 5.