Subfields not saving delta/order correctly.

I'm new to Inline Entity Form, but I have not found this issue tracked yet.

I have a multiple inline entity reference, which in turn, also has a multiple inline entity reference.

The relationship is like so:
first-level Entity -> second-level entities -> third-level entities

Surprisingly the module handles this very well, except for one caveat:
If I click "save" on the second-level inline form the delta/ordering of the third-level entities is not saved. If I click save on the parent form (first-level, ignoring the innermost save actions) the delta/order is preserved and saved correctly, so likely this is a naming/id issue w/ the ajax request.

The issue exists for me in 7.x-1.2 and currently in 7.x-1.x-dev