If this is from a qualified tax-deferred type account to Roth, this is a Conversion. Not a Rollover.

401(k) ==> Trad IRA is rollover

401(k) to Roth is taxable conversion.

The 1099-R is from the provider for the money out of the other account. Then, you do the next step and address where the money went.

"The taxpayer funded the taxes from another source."

Exactly. If this was done directly, there never is any withholding. If this is done through the client, there is required withholding (not taxes). In this case, it's still taxable anyway (unlike 401(k) to Trad IRA). They get the benefit of a gross redeposit instead of a net, for the conversion.

You posted this not in the community help section, It's only an error until the entries are made and that resolves the condition.