I wasn't clear about the cause of the intermittent connection. That was a wire that had come loose from a wire nut in the outlet's box. The insulation was kind of shiny, indicating to me that it may have been sparking in there. I think everything's okay now. Mostly I was just freaked out by the 30V current on the switched outlet while off, but people seem to think that that's okay, so I'm willing to go with it.