It does seem strange that no one has claimed credit, but that could be a new MO. Keep ‘em guessing.
I believe you’re right. When was their big leader killed? Any correlation?
They won’t claim credit until their overall campaign ends or is exposed.
If they have a dozen more soda cans being passed from hand to hand to baggage handler.....
They will just let them go off, and not provide clues that could end the program prematurely.
Worst case, they have sent people into Europe who can both make TATP and pack it into soda cans. I would assume that this is the case. Mosul University had full chemistry and engineering labs, and they were training jihadists to take their knowledge on the road.