It’s possible the jackal had rabies which is why it was feisty enough to attack a lion, but there are documented cases of jackals growing bold enough to attack lions, cheetahs, even leopards (which often prey on jackals). Normally the encounters end with a dead jackal, so this one was pretty lucky the lion decide it wasn’t worth the time.

And if they’re going to confuse a black-backed jackal for a fox, the least they could do is use the funniest pic from the series. [source]