dddd

I don't suppose any spacers carried over from the old hub, and different hubs/wheels often have enough dimensional differences to require re-adjusting the derailer, but I'd be concerned if there is any real "snagging" as you suggested, which might cause interrupted movement of the cranks?
I'm almost assuming it isn't that bad, cause then there would be a need for a saftey margin in terms of the chain clearance.

Is there any spacer at all between the back side of the cassette and the fulcrum freehub body?

Does the cassette spin straight when it's rotating with the wheel?

You and F.B. discussed the hi-limit screw, so now assuming it's as tight as will still allow shifting to the smallest cog?

Perhaps your question could also be directed to Fulcrum's customer service dept. A wheel can be built stronger and thus lighter by positioning the cassette closer to the frame, so perhaps they exploited this to the point of being incompatible with a select few framesets. I'm sure that they would want to know about this, but they may ask that you bring the bike to one of their dealers for evaluation.