Well, I said I'd be testing this out in a clean save, and so I did. And here's the update:
Two glitches confirmed, in a completely clean, no CC, no store content, no mod game (Windows 7, downloaded ITF, to summarize from previous answers from previous post):
1) No "pet horse" interaction on any horse, whether it is a pet or a wild horse.
2) Just noticed that, despite having horses unchecked, they are being adopted (possibly from the wild?) by Sims. There aren't any characters in Moonlight Falls, which is where I am playing this save, who already have horses. I just went to the Festival Grounds, and lo and behold, there's a horse I'd seen wild, with a brand new name, wearing a saddle. I double checked my options, and yes, horses are unchecked. So even if they do spawn, NPCs should not be adopting them, not even from the wild. It may only be a glitch in my particular game, since I've been playing this test save for several hours and the longer you play, the more bugs you get.
And I repeat that the issue with leaving work early seems to be that work is allowed to be canceled by the PlumBot "scan" interaction (and possibly other social interactions from other Sims/types of sims). I think this glitch popped up in the past with some other expansion, but I don't remember when or which. I guess they accidentally didn't prioritize work over new social interactions?
If ec1ipsse is reading, could you please check and see if any sims/pets are attempting to interact with your sim at work in the present world? I only had my Sim's work interrupted in the future, so I'd be interested to know.
Would anyone else mind to test the horse-related glitches to confirm? Note that, again, this is happening in a clean save, no mods, no CC, no store content whatsoever, not even registration rewards.
I'd already reported them, but since I did have some CC and had then installed mods, I wanted to be sure that these things still happened in a clean save. So again, this is just a post to confirm glitches in a factory-reset save.
Edited to add: I should have said this sooner, but thanks, Crinrict, for compiling the list of glitches and working so hard to help everyone out. It's a big and difficult job and I'm glad someone's out there doing it! (And I'm sure so are the Sims development team, who will probably use this thread to find glitches that need to be fixed when/if there's another patch released!)