If this K-1 showed items were taxable, they would be taxable to your IRA. They would never be taxable to you personally since your IRA is the entity that owns the investment, not you.
Does box 1 of the K-1 indicate that the entity is a type of retirement plan? Is the I2 box marked? If the IRS does not recognize that the owner is a retirement plan, they would probably treat the income as yours rather than as income to the retirement plan account. Note that the instructions for Schedule K-1 indicate that for an IRA the partner information should be that of the IRA custodian, not you. I would think that the same would be true when the partner is an account in a qualified retirement plan like your 401(k), but I can find no specific IRS guidance saying this. If the K-1 is in your name and SSN, I can imagine that the IRS might think that it is your income, particularly if box I1 does not indicate that the type of entity is a retirement plan (rather than an individual) or the I2 box is not marked.
