Just telling the IRS that this partnership is owned by an IRA is insufficient; a code V in box 20 already means that you personally are not the partner (since an individual cannot be a tax-exempt entity), but they'll still hold you responsible. Perhaps the problem is that the IRS examiner failed to notice the negative sign on the code V amount and instead treated it as a positive amount that would require the IRA to file Form 990-T and pay UBIT.
