You should override BeforeEntitySave now instead. OnBeforeEntitySaveis called before the entity is actually send off to the query producer. Because the logic has been changed internally, SaveEntity is not called recursively: a queue is build up front and that queue is persisted. To be able to intercept a save of an entity, OnBeforeEntitySaveis added.
See also 'Migrating your code' in the documentation, under 'Adapter'.