Thanks for the query.
As your ultrasound
report shown that there are no retained products of conception the brownish discharge may not be related to abortion
That could be post ovulatory bleeding if the ovulation returned after abortion.
As it is only minimal discharge not associated with blood or pain abdomen no need to bother.
The word inhomogenous indicates that the endometrial layer surface is not uniform.
It can be because of shedding of endometrium during abortion.