Unable to use substitution macros in classes config section

[adrienlauer]

It seems that values of the classes config section are not evaluated properly or something is blocking that ability. So a section like this will always have it's mongoDbDatabase value empty:

classes:
  com:
    inetpsa:
      msj:
        core:
          domain:
            model:
              invoicingevent:
                defaultRepository: org.seedstack.mongodb.morphia.Morphia
                mongoDbClient: mefistoMongoClient
                mongoDbDatabase: ${env.MONGO_DATABASE:'MSJ_DB'}
              sourceevent:
                defaultRepository: org.seedstack.mongodb.morphia.Morphia
                mongoDbClient: mefistoMongoClient
                mongoDbDatabase: ${env.MONGO_DATABASE:'MSJ_DB'}
              cancelevent:
                defaultRepository: org.seedstack.mongodb.morphia.Morphia
                mongoDbClient: mefistoMongoClient
                mongoDbDatabase: ${env.MONGO_DATABASE:'MSJ_DB'}