3.5.1 added a few nice features but ended up breaking others. I came from 3.0.2 loaded from the factory on a 2013.
1. BLUETOOTH AUDIO. 3.5.1 added an elapse timer shown on the Bluetooth audio screen. This timer is constantly out of sync with the actual elapse timer on my phone (using Spotify). For example, if I select a song from Spotify on my phone and start it from the beginning, the elapse timer will correctly show 0:00 and start counting up. But when I switch the track using the car screen or steering wheel controls, the elapse timer on the next song will start at an arbitrary number like 1:31 and start counting from there. Then once it reaches some other arbitrary number, IT WILL SKIP TO THE NEXT SONG ON ITS OWN. This is extremely annoying and obviously broken.
I did several master resets and delayed reboots and finally, the elapse timer stopped working (it would just stay at 0:00 while songs played). When this happened, the auto-advancing track issue disappeared. Yesterday however, as I got into the car, the screen had a "Performing Maintenance" message and guess what? The car "fixed" itself and the elapse timer is working again and of course auto-track advance problem is back.
2. NAVIGATION. When I "broke" the elapse timer above, POI icons on the map were not toggling on and off as imputed. For example, I was driving along and decided to go into my maps and noticed that gas station POI icons were showing... I go into the settings to toggle it off but they would not leave the screen. This issue fixed itself when the car did its own maintenance yesterday.
So I must choose between breaking the elapse timer (fixing the auto-track advancing issue) and having POI icons broken, or having the the icons working but having songs skip to the next track on their own...
I've only had this car for 3 months and it's my first Ford, but this is a joke... a cruel joke.