I'm very thankful that I found this thread. I've had this problem for about 8 months. It started after a few weeks of ownership and I initially though it may have been due to some storm damage that the car suffered early on in its life. That was almost 4 months getting fixed by the time the car was assessed, parts were shipped in, and the work was done. So, I didn't really think much of it. But when we FINALLY got the car back, the noise persisted. Then winter hit (not a proper Winter, a Melbourne Winter. 30F - 60F) and the noise got worse. These are a few of MY observations which agree with others' observations on here (hence there will be some repeats in this list).
1. The noise sounds like a popping noise. Not a rattle. It sounds a little plasticky, but also a little rubbery. It's not a rattle. I just wanted to stress that it's not a rattle because the numerous references to rattles in this thread is the main reason I kept on skipping over it since the noise isn't a rattle.
2. The noise is temperature related. This is something that I have seen touched on in this thread (but I started at about page 15), but not emphasized. The noise definitely reduces after driving around for a while and things heat up.
3. The noise is related to high frequency suspension movements. What do I mean by this? Shock Absorbers (or dampers) have high frequency valving and low frequency valving. Think of a high frequency as driving over cobblestones, and low frequency as driving over a speed hump. This noise, in my case, does not manifest itself with low frequency suspension movements, only high frequency.
4. The noise is not related to tire pressure. lower tire pressures will increase the damping properties of road noise, indicating that the noise is generated by something upstream of the tire/road interface (also previously noted on here)
5. The noise is not related to steering input. The noise manifests itself at a variety of steering positions
6. The noise is not a resonance. There is absolutely no quality in the noise that presents as any form of 1st harmonic resonance.
I've given a lot of though to this. I do a fair bit of mechanical fault finding in my daily job. I was recently tasked with finding a resonance in a gearbox which had no correlation to any gear or bearing fault frequency. Turns out the problem was a solvent contaminant in the gearbox which had stripped the internal lacquer coating from the castings and been deposited on the bearing races by the lube system, which had then interfered with the lubricant film to cause a resonance that manifested at a different frequency every time the gearbox was run.
Based on my experiences and the fact that the issue is temperature related, I believe the problem may be related to the internal high frequency valving in the damper. Some of the fixes mentioned in this post may mitigate some of the noise being transmitted to the cabin, but I don't believe it's a fix of the core problem which is supported by the fact that some people have experienced reduced noise, but not elimination of the noise.
It also seems that the only permanent fix has been a strut replacement which has worked for some, but if the replacement strut has the same defect, the problem persists and therefore others have had no rectification to their problem.
Then again, I could be completely wrong! But the noise definitely seems like a damped mechanical knock, with the damping giving it a plastic/rubber sound quality.