Yeah, got it working on a newer save. I just never cared enough to truly investigate why it wasn't working on my save file.
I probably fucked something up when I was screwing around with editing things.
No, it absolutely isn't supposed to be like that.
I've never had that issue myself, so I don't know what happened, but I suggest either starting over again, or maybe getting a fresh install of the game.
Edit: Had been a bit since I played, so I completely forgot but!
If you're playing on Hard, the Loan quest isn't canceled upon Prologue completion. You're most likely playing on Hard rather than Normal, which is causing your issue.
It's not "more popular" because bestiality is a fringe fetish.
It's illegal in most countries, and most humans consider it, and I quote: "morally reprehensible".
I personally don't see what's wrong with it, unless the animal in question is being forced into the act.
Note: "Fringe fetish" is the opposite of a normal fetish, (ie: anal), it's something that isn't common.