Sometime in the last couple weeks, it appears that the apps pinned to the nav bar, or in the app tray are no longer there.
Clicking "Add Apps", and then attempting to click the star yields no result. I can click on the app icon in the Add Apps screen, and launch them that way.
All channels on the server have this issue. All using the default theme. On current stable release, and updates are current.
2018-09-09 Update: Resolved! The issue stemmed from the "term" table in the Hubzilla database having the "crashed" status. After repairing the table, the app tray functions returned to normal.