I am having the exact same issue. So suprised at the HUGE number of people who are experiencing the same thing with this terrible Samsung washing machine. I googled on internet - and found out that my machine actually has a recall. Samsung recalled 2 million machines (not for this purpose). But I can get $ towards a new machine. Mine is not even 2 years old. I can't stand the dirt & mold on my clothes any longer. Buying a new one this weekend. NOT SAMSUNG EVER.
I started with this issue weeks after I purchased. Repair guy told me unless i could tell him the exact thing wrong with it he could not fix it. I told him the problem i was having and he said well is it the motor, the pump, what? Needless to say it never got fixed and three years later it is absolutely disgusting. I go to laundry mat because i can't use it and looking for a new washer.
I too have the same problem with residue/debris in my top load washing machine. I bought my machine 3 years ago which was recalled and opted for a identical new machine to replace it about 2 years ago. I run the self clean cycle regularly with vinegar and tried bleach which really does not improve the situation at all. I am very concerned that there is a mold or mildew problem because the machine never fully drains. My husband checked to make sure we did not have plugged hoses..we do not.
I just called to discuss my problem with a samsung customer service agent and she told me that I will have to pay for a service call since I am out of warranty. Obviously this is a serious issue that Samsung is having and I am very disappointed with the response from the company.