Integration Connector Warnings

I have a number of integration bus connectors setup which all seem to load fine when the site is first started or performing System -> Restart Application, however I have noticed that when clearing the cache 'System -> Clear Cache' it triggers the connectors to be reloaded at which point all except one of them fail to load with the message:

Failed to load connector '<Connector Display Name>' with assembly name 'CMSAppAppCode' and class name '.<Connector Class Name>'. Please check connector settings.

Note, the connectors are in a separate project named CMSApp_AppCode and within the root namespace.

The only differences between the one that loads OK and the others that fail is the base class they inherit from and the integration subscriptions they use. The one that loads OK inherits directly from BaseIntegrationConnector and only uses the base class method SubscribeToObjects. The ones that fail all inherit from a custom class which itself inherits from BaseIntegrationConnector and these connectors also use custom subscription classes that inherit directly from ObjectIntegrationSubscription.

I have tested inheriting directly from BaseIntegrationConnector which seems to fix it, however I need the custom class for dependency injection purposes. Is there an issue with not inheriting directly? Is there a workaround?