You are looking in the correct place for your software. Your 8.4 has navigation and therefore uses the same software as the 12 inch screen users have. Mine does not have nav and I have a different software version all together.
There are definitely newer software updates for your truck and this could be your issue. If you browse through the section dedicated to the 12 in users you may find some useful information. I would think the dealer could manually load the latest software for you, not sure why they wont. With that said have you connected your truck to your home wifi, this could help with receiving updates?
Also, have you tried to use a different phone to see if the issue persists? Do you experience the issue when your phone is physically connected and through Bluetooth? It definitely sounds software related to me but I am trying to rule out all other variables.
@Jimmy07 is a genius on these systems and I believe he has posted newer software versions for your system you can download and upload yourself. Try searching through his posts to find it or make a post in the section dedicated to the 12 in users and someone will help.
**EDIT** See post #65 in this post, this should help.
Had a typo in my post, it's 26.17 not 26.15. I have seen on a few other forums a couple people have Android or Apple connection issues after the update. Very inconsistent. Maybe something to do with the phone not Uconnect. Also a couple reports of restarting but not everyone. So random.
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