I've had that just once in a while in my 2018 S75D. I think that it has only happened when my air suspension had raised itself above standard height (due to location) and I accelerated hard. Just something you might want to investigate.
I think mine only raises itself when it notices via GPS that it is in the same area where I've manually raised it previously. Not entirely sure if mine ever raises itself otherwise, but that might vary by model or date of manufacture. My car is a wonderful vehicle of mysteries.
Exact same problem here too. (2018 100D). It's very reproducible on moderate-to-hard acceleration. I brought it to the SC in March, and the lead mechanic confirmed it. They took apart the frunk and couldn't find anything loose. They then put it on the lift and found that the Left front axle nut was loose, and that the wheel bearing was damaged. They replaced the bearing, torqued the nut to spec, and the problem disappeared - until yesterday! I have an appointment this coming Monday. Ugh.
I set the car to suspension to the lowest setting and still heard the noise so I doubt it has to do with the suspension. For all the people who have the noise what have you done about it?? Considered it normal or attempted to have it rectified? Seems like there's quite a few people with the problem but not many solutions....
Did anyone find out what caused this? I have the same noise in my 2018 S75D since I mounted new wheels with ET35. (Not the drive shaft vibration noise, it had that before.)
The noise is intermittent, only appears at full throttle, when not in low and seems most common when flooring it from 25 mph. Sometimes it’s a creaking like in the video above and sometimes just a single click.
I tried swapping back the original ET40 front wheels and couldn't reproduce the noise. Put on the new wheels and the noise was there again, possibly less frequent than before.
It’s strange if a 5 mm offset difference would cause this but it doesn’t seem to be a coincidence…
Likely its resolved by this new service bulletin SB-19-39-001 R2 Dated 25 June 2019 applies and is a replacement of LH front drive unit Clovis mount and both front halfshaft. Applicable to all MX & MS 2014-2019 (before May 2019)
There are some other threads on this with more info.
In brief, it's a common issue. The first fix that I described above (axle nut and bearing replaced) was short lived. I had to bring mine in again and I actually had to tell them what I knew was wrong based on this forum. (Crazy, huh?) . They replaced both half shafts and the jack shaft. That solved it. They said it will likely happen again at some point as it's a design issue. I don't know what it would cost out of pocket, since this was a warranty repair.