I've seen such difficult to follow code in Java, and I complain about it every time. But having multiple inheritance isn't the cause (because Java doesn't have that). Nor does having multiple interfaces with default implementations have any real impact (at least in _any_ case I've seen).

The only real difference I see between multiple inheritance and multiple interfaces with default implementations is constructors. And they can be handled in the same way as default implementations; requiring specific usage/ordering.