Obviously the dead ghost is far to lively, we should kill him again.
Besides, the prince is displeased about Sebille killing the Master before he could talk to the Shadow Prince after he did already talk to the Shadow Prince. So he will just talk to the Ghost instead and totally forgot that he had just moments ago literally the same dialog already ... but hey, at least this time Sebille can make stupid comments on his talk instead of him just doing his thing when she was hiding in the shadows like all those other Shadow Assassins.
But hey, I am doing my part to improve a game in early access. Bug reported.