You describe the noise as a 'creaking', so maybe it isn't the same problem I've had (which I describe as being more of a 'click'). I was going to post about a recent instance of my version of the issue anyway, though, so I'll pile on here...
I can't remember if all four LEAFs I've owned had the "noise on motor torque direction change" issue, or if only three did. In each case, the dealer's mechanics found the problem to be an assembly issue with some nuts having to do with the front axle(s) (or maybe u-joints?). A couple times, the fix was to apply grease (?!) and re-tighten; another time the nuts were replaced as well. Most recently, the issue began to appear on my current 2018 LEAF, but was intermittent at first and not terribly loud. Rather than burden the shop with a difficult-to-reproduce issue, I just kept driving the car until the problem was repeatable. On a road test, the tech instantly confirmed that "oh, yeah; you've got axle-clicking", ordered a set of replacement nuts (not the kind of thing they could afford to just have lying around, I guess..), and had me come back a couple days later. When they set to work, though, they found that the axles themselves needed to be replaced as well. They supplied more details, but I'm afraid I only pretended to understand them. I don't know if they were correct to say the axles were of defective manufacture, or whether my delay in having the problem investigated allowed them to become damaged. They felt that replacing the axles was a safety imperative, so I had to leave the car with them for a day while they scurried up replacements. The new axles have eliminated the problem, though, and it was all done under warranty at no charge to me (including a day's use of a loaner car).
Whew; sorry for the longwindedness. All this was to suggest that you don't delay too much in having your problem looked at, if it's reasonably easily reproduced. Hope your noise is solved. And it could be a bushing like you say.
