I am S4 mk3 user. I have been facing this for a few months now. The only way to resolve this is to restart the software which isn't ideal when you are in the middle of the gig.
Update on behalf of the OP
Following the "Reimport a backup TRAKTOR Settings file" steps in this article helped resolve the issue.
The remix deck usually only stops if you stop it manually via the corresponding deck control. It doesn't stop if you stop a sample. Are you saying that pressing Play/Pause or Cue doesn't stop it?
