Remember that Ghost is both a Duration card and a "Throne Room"-like card. That means the time it stays in plays is governed by the rules for both card types. Since Ghost played a Duration card (Captain) in your two examples, it will stay in play as long as the Captain stays in play, which is one turn longer than it normally would, when it plays a "simple" card like Smithy that unconditionally gets discarded during Cleanup.
On turn 11 you played three times a card named Captain. Twice it was the same card, the Captain set aside last turn and then played by Ghost, once it was the Captain you played from your hand. So on your next turn (Outpost turn), you got 3 Captain "next turn" effects. This seems OK to me.
The Ghost played the Captain twice on your Outpost T12 turn. As explained initially, this makes the Ghost and Captain stay out for your normal T13 turn. And since the Captain was played during your Outpost T12 turn, it of course has its "next turn" effect in your normal T13 turn.
I think you got confused by the presence of the Ghost and assumed it would play the Captain again, when what you saw was the "next turn" effect of Captain, which is of course the same as its "this turn" effectt.