When Map2BeanTransformer.readSimpleValue() line 197 encounters a class name that cannot be resolved, this problem is only logged as a "minor" and without details in DefinitionProviderProblemLogger line 89. 

Not finding a class should be considered a major problem, as configuration and classpath don't match and this can lead to fatal problems. This should result in an ERROR being logged with details on configuration location and classname. Currently, this is logged as WARN instead, and without any details.

More details currently are only logged if Magnolia is not in development mode, which doesn't make much sense anyway?