I know this thread is a year old, but having the same issue on my 2021 tax return. The reply, however, appears to have mis-understood the situation. The 1099R was documenting the in-plan conversion from a Traditional 401k to a Roth 401k. It wasn't documenting a Designated Roth [401k] to a Roth IRA as the reply appeared to reflect.
I've also found that within Turbo Tax, you can keep the Distribution Code of G, and have the conversion not impact MAGI or ability to contribute to Roth IRA, if you answer the question following this entry as "No, this money didn't roll over to a designated Roth 401k or 403b account." Instead, show the money having gone rolled over to a Roth IRA. That wouldn't appear to be the correct answer, but it correctly reflects the taxes IF an in-plan conversion from a Traditional 401k to a Roth 401k doesn't affect the modified adjusted gross income (MAGI) (which would make sense since converting Traditional IRAs to Roth IRAs doesn't affect MAGI). The question remains:
"Do in-plan conversions from a Traditional tax-deferred 401k to a Roth 401k affect your MAGI?" (It's already firmly established that conversions of Traditional IRA to Roth IRAs do not affect MAGI.)
