This is a bug that is currently effecting the compatibility with the IBM4690-TLOG schema project.
In the IBM4690-TLOG schemas there is a parent choice with dfdl:initiatedContent="yes" that contains groups of choices. The child choices define an initiator, but the initiator does not seem to be getting passed down the the elements contained within the choice inside the child choice (3rd level choice), causing the following SDE:
Schema Definition Error: Enclosing group has initiatedContent='yes', but initiator is not defined.
Here is a simplified schema as an example: