Just sharing my experience and to document this here online if others have a similar issue. I've been using the car vent mounts with magnet without issue for my iphone 7 plus for the past year. Specifically the Evutec AER series, Karbon Black with AFIX When my new iphone 8 plus arrived a couple of weeks ago, I slipped the Evutec case on it to protect the phone, it was a bit tight but it went on ok. I was driving home from work that day and I glanced at my phone and I could see the error message "No SIM installed" appearing, within a 20min period the phone was connecting and disconnect from the network with the no sim installed happening on a number of occasions. I had the phone mounted to the vent magnetic holder during this trip. Once I got home the network connection was ok again, I did a full reboot on the phone - also popped out the sim card tray and inspected it - all was ok. I switched the case over to a spigen clear one that I had for a few days, had no issues. Yesterday I decided to put a metal mounting plate on the Spigen clear case to try and ultilize my magnet vent holder again. And within a few minutes the same issue happened again, no sim installed error appeared. I took the cover of right away and stopped using the magnetic vent mount. At least in my instance there is a correlation with the use of the magnetic vent holder and my iphone 8 plus. So wanted to share this with others. I know about the wireless charging and glass back case on the 8 plus, but I figured that I could use at least for a while the AFIX mount option when not charging the phone. It appears that the magnetic field has an impact on my sim card/electronics. Anyway I'll go back to using a regular vent mod for now such as the Kenu one that I have for now. Thanks for listening.