So they'll have to wait until that loan is paid off.
However let's say the buyer wants to use FHA to purchase a condo where the default rate in development is over 15%. The development may not qualify for FHA financing and therefore a loan would be denied due to property the property. The buyer is still qualified to buy but they can't buy that particular condo. Is that what you are asking?
And no I haven't had a qualified buyer denied a loan.