When I Switch from Run to Pause (the global one, in the Status Bar), it only stays paused about ten seconds then it magically un-Pauses itself.
This hasn't been happening for long.
If I Pause Selected download fileset(s), that works correctly.
I did by mistake change (an I think unrelated) setting last week: I clicked the red toolbar button that Enables Automatic Shutdown. I've since successfully disabled that.