For anyone experiencing the system tray icon problem, please post screenshots (if you haven't already), and also note which Windows 10 version you are running, and the type of GPU you have, in case any of those things are parallel to the problem (although I don't believe they are).
I just updated to Version 1803 Build 17134.81, and the problem remains.
Like I said, I did report this in the Feedback Hub during the Insider Preview, but apparently those don't get visibility unless there are significant "upvotes" on an issue. This one is a bit "nuanced" with (probably) relatively few people noticing the problem.
Still, I do have the ability to create Microsoft Premier Support tickets at work, and I'll submit one with reference back to this thread, in the hopes that someone who matters will see it. The more detailed information there is in here, the better.