Thanks for your responses Erik and @Patrick Roberts ! I think it was conventional of the type Patrick described.
The loan officer was aware borrowers planned to use it as a portfolio rental so the only thing this "special loan" would accomplish is burning the relationship. Thus a win for them would be to void that term, right? Even though interest rates have gone up 1%. What would be the right way to approach the bank about this, and who at the bank could void this term of the loan agreement?
BTW, the closing was done remotely by one of the 2 borrowers, and they explicitly limited the power of attorney to only what was "Necessary" to execute the loan. Since it was discussed with the loan officer the borrowers were seeking to create rental portfolio assets, they likely knew the borrower who was not present at signing would not have signed that, but apparently the one who was there signed everything presented to her to the point of her hand cramping, without being aware one of those signatures countered their plans for the purchase. So I doubt it would be enforceable unless the doctor loans "necessarily" include that term. But I don't know how a legal dispute with the bank would pan out and would avoid that if at all possible to just approach them politely and have them void it. Any suggestions for how to handle this and still turn it into a rental (it will cashflow) are greatly appreciated!