My features of a PostGIS layer are displayed in the map canvas in QGIS and projected properly at the right place.
They are not selectable in graphically in the map. But they are selectable in attribute table.
So it does not seem to be a problem of granting rights to select/edit the data.
My PostgreSQL 12 server contains 2 databases. All tables of all schemas of just one from the databases show these behaviour. In the other database every geodata-behavoiur is as expected in QGIS.
Inserting test data/tables in the PostgreSQL scheme via QGIS-database-export throws following exception: Function addgeometrycolumn(unknown, unknown, unknown, integer, unknown, integer) is not unique.
(It's no problem to create (new) views within the misbehaving scheme)
Any idea what went wrong and how to fix it?