Just a few thoughts on this problem:
If an update removed the seat icons, I assume installing another update should fix the problem.
When I searched for the 3.8 update, the Sync website asked that I do a vehicle heath report before the update. I think this indicates to them which version is currently running and generates or retrieves the proper update file. Then the update was available for me to download. However, I did get the Lincoln display as others have, which was fixed by the patch.
I noticed the autoinstall file contained a default. I suspect somehow your previous version was different than what is in the list and you got the default files, (i.e. a bad update file for your truck). Trying to reinstall 3.8 will not work because it probably isn't in the list of "install from older version" because it already has the latest version number, so it just reinstalls the default. That is probably why the Ford dealer failed to fix it.
The fix would probably be to get a good full 3.8 update file (not the patch) and add your current version to the bottom of the autoinstall file, like this:
;;;
;;; The following tags are software versions supported by this update
;;;
[SYNCGen2_3.08.XXXXX]
This should hopefully reinstall the 3.8 updates, and include the seat icons. There is a big assumption here that the seat icons are included in the 3.8 update. If not, this would take further digging into the problem.
Note, this is all just a guess on my part. I am still trying to work on changing the initial splash (white - door open) screen before the Raptor logo, and I am having problems, so I don't fully understand the software syntax yet. But I will try to work on it. Perhaps others could assist with my guesses on why the seats disappeared.
It might be helpful if you send the file you used for the update that caused the problem. This may provide the section of the update that changed the seat icons in the first place.
John
NASA Software Engineer
(Why yes, I are a Rocket Scientist)