The official FMVSS 141 requirement didn't take effect until September 2019. My former 2018 Model 3 had no noise maker at all (silent), whereas my 2016 ELR did (GM just proactively doing this). Agree though that with the current crop of EVs, Teslas still sound more tame than what GM is doing.
But if I understand this recall, it isn't that the sound is too quiet (or too loud). It is that it doesn't modulate the volume such that you can tell if the vehicle is accelerating or decelerating. The way the recall is worded, it sounds like this isn't being done correctly...
"
Relative volume change to signify acceleration and deceleration. The sound produced by the vehicle in accordance with paragraph S5 shall change in volume, as calculated in S7.6, from one critical operating condition to the next in accordance with the requirements in Table 7."
Or basically, from 0 to 19 MPH, the sound volume has to increase by +9dB as the vehicle accelerates - after which point no noise is needed. And for deceleration, it needs to get quieter by the same span.
Probably there is lag or other conditions that cause the car to not comply with this, or GM just calibrated it wrong. GM had a similar issue on Lyriq with a bad OTA update in summer of 2023 for certain cars (before they stopped the update), which comically required a dealer update to correct.