Rules actions with entity argument get their entity arguments unwrapped

I'm building a rules action for loading entities that have been related to a source entity with the relation module.
The rules action takes two arguments, one entity, and a relation bundle.
My problem turns up when the callback is passed the raw entity object, instead of an entity wrapper.
Information about the entity type is now lost, and I can not query for related entities, as I can't uniqely identify the source entity.

This could absolutely be something I've missed, but it looks like an oversight in the rules or entity module?