Has anyone ever triggered those? I died at some point, and it showed like a prologue of the start of the game, where you control the character before his contract with death. At some other point, it showed a guy painting some big panel. Then it goes back to the last saving point. Is there a way to control how those triggers, or does it seem completely random?

Don't know if they're random or triggered by certain numbers of deaths or story progress or whatever, but yeah, I've seen several of them. Three or four maybe, pretty close together, a short time into the game. But none recently.