Doctors Loan/Conventional Loan = You Must Occupy the Property forever?!?

[Andrew Pierce]

Hi BP Mortgage pro's,

theoretical scenario: a doctors loan was used to buy a primary residence rental portfolio piece, while talking with the loan officer @ big bank name about how it would be used as a rental portfolio piece after eventually moving out.  Then a couple years later, discovered that a piece of paper was signed at closing which was never read and in fine print says something about the home being owner occupied throughout the duration of the mortgage... wtf?   

Is that necessary terms for all doctors loans?   Does that make any sense to put in a 30 year loan package, or standard by any means?  I thought all 30 year mortgages require only 12 months occupancy.

It seems to be a lose-lose since the lender loses the interest on an otherwise good loan if it had to be sold, and they gain nothing.  Or if they already sold it on the secondary market, still, what could be the reason for this having been added into the fine print?