Check the instructions. There is a machine clean cycle called Pure Cycle, pg 30 of our instructions.
I think the agitation is very vigorous and Pure Cycle is NOT to be used with clothes, but only to clean the machine. This washer is designed to be water saving and perhaps needs to be cleaned this way periodically. We have had a Samsung top loader for several years and have had no smell. We haven't had to use the machine clean cycle, AFIK, but different needs for different users.
EDIT
We have since used the machine clean "Pure Cycle" once or twice just as a precaution.