The Select permission was denied on the object ‘extended_properties’, database ‘mssqlsystemresource’, schema ‘sys’

When you see an error, such as in the following screenshot, you may consider why your database is trying to access a hidden system database.

The reason for this error is that all privileges are granted when authorizing the login on the database as you see below.

As a solution;

Just remove the privileges in the db_denydatareader and db_denydatawriter roles.