I would like to report the same issue
They are not just hidden, they simply don't show up even when running
It seems that when my computer starts and it starts Classic Shell, from then on any icons in the taskbar that have not shown up before Classic Shell started somehow get suppressed. As a test I stopped Classic Shell from starting when Windows started and all icons from then on showed up. So for now my work around is to have Classic Shell on a delay when starting up.
I'd really like to see a fix for this. I went through the trouble of wiping and reloading Windows to fix the issue when it ended up being this all along. So I'm not impressed
