Been having an odd problem with our Discourse instance recently.
It seems to be stuck on Currently Upgrading (even when there are no upgrades available):
There is no way to upgrade from within the web ui. When there are upgrades available, when I click on it the console window is just a blank screen. I need to do a ./launcher rebuild to upgrade, and even then it sometimes hangs on the stop app command, and I have to reboot the server to get the forum back.
There is nothing in the logs that I can see that pertains to this error.