A Form 1099-R with code G in box 7 and the IRA/SEP/SIMPLE box marked reports a distribution from a traditional IRA that was directly rolled over to a traditional account in an employer plan, not anything to do with a Roth account. A Form 1099-R with code G in box 7 and the IRA/SEP/SIMPLE box marked can never have a nonzero taxable amount in box 2a, so it seems clear that the preparer prepared this form incorrectly. I suggest escalating this with the financial institution.
You are not permitted to simply change the code in box 7. If the form is incorrect and the preparer will not make the correction, you must file a substitute Form 1099-R (Form 4852) and provide explanation. Doing so will prevent you from e-filing.
