You wouldn't believe how common it is for a residential agent to think that they can sell a duplex, 4 plex, etc by the same techniques that they use when selling a house.
It starts with the contract. If you use the residential form, you leave out all the clauses that apply to income property; like the seller providing income and expense information, that the seller can't repair, rent or cancell any tenants without buyer approval, transfer of deposits, contingency on approval of rentail agreements, etc, etc. But, if you use the income property contract, because 2-4 unit properties also require all the mandated disclosures used for single family units, the contract is also inadequate. Frankly, the only way to resolve this is for you to prepare a standard disclosure for the Residential form, adding all the good clauses that protect the buyer or seller.
More next time.