I have a 2020 GMC Sierra 1500 with the 3.0L Duramax. I was having this issue and just got my truck back today from the dealer. They replaced both rear leaf springs. My factory warranty had run out but it was covered under the extended warranty I purchased.
Mine went back to the dealer Monday on a rollback for the second time with this issue. I also informed them of this problem but still have not got my truck back. I also told them I wanted a new battery since this was the second time and this time the battery was drained down to 2 volts.
I had the same problem when I first got my new truck. I had to pull the SD card out and reinstall it. After I did that I had no more issues with the speed limit not showing.
It looks like the reveal for the 2021 Tahoe/Suburban os set for 12/10/19
http://gmauthority.com/blog/2019/11/all-new-2021-chevrolet-tahoe-and-suburban-will-be-revealed-december-10/
Just in case anyone was wanting the new charging module, I found a dealer that has them in stock and selling on EBAY.
https://www.ebay.com/itm/253405415313?ul_noapp=true
I just picked up the new S8+ today and it charges fine in my truck...I just have to put it on top of the rear lip of the charging pad for it to work. It fit fine in the cutout but wouldn't charge until I moved it up on the lip, Strange!!
I had Safelite put one in my Tahoe and they did a great job. I did specify that I only wanted OEM glass and that's what I got. It took 2 1/2 weeks to come in but it was worth it.