I was riding my beef as usual and it shook the saddle off. I fed it some stuff, and saw that some shadow creatures were coming, so I pressed the attack button in between (not force attack). As you can guess, I ended up attacking my precious beef instead. Because I was in the caves and because there are no roads down there, there was almost no way for it to lose aggro on me.
I think my mouse was hovering over the beef, although I'm not 100% sure on that one, and I couldn't follow the latest changes, so I don't know if hovering the mouse over to choose an attack target is intentional now. Even if this is the case, I'm sure attacking allies this way isn't intentional, or at least shouldn't be at all.
I would appreciate it if you guys could solve this issue. Thanks for your time and have a nice day.
Feed a beefalo that shook its saddle off, stay near hostile mobs, (hover your mouse over the beefalo?), press the attack button.