Not sure how it happen, but yesterday all my entities shown in the Home page was gone after restart of HASS.
Did some group configuration changes and some customizing before restart, have restored back to as it was before with no luck.
In my groups the entities are shown as before, the entities are only missing in the Home page. The States page are also showing all the entities.
Im guessing you setup a default view, if so, only the items you specify will now appear on the front end. Everything else will be hidden until specifically added to a group/view
Forgot to say, but I removed all the groups from my configuration to test with no change else then that the groups where gone.
So it could not be related to the group configuration.