I thought I saw a mention of a non-Firebrick case in the comments. I can't see how a router could make an iOS box fail like that, well I ought to know more about it, it could be that the iOS device tries to reacquire an IPv4 address when it does a BSS handover.
I'm more inclined to think that something as nasty as that would be a tread on the wrong floorboard kind of bug, that you need say a Firebrick plus x plus y etc to be the correct stimulus to make something else fail. Instinct would point the finger at Apple. But also because, looking at it from another angle, an argument could be made that Apple have screwed up regardless of the details, in that there is no earthly reason for them to end up with an IPv4 link-local address (169.254.x.x).
I would definitely think that a Firebrick has to be blameless because it knows nothing about wireless LANs and any plain networking protocol bug - perhaps relating to DHCP - would have been spotted in traffic captures or logs by now.
Just a load of guesswork from me based on far too many months of my life wasted, but zero knowledge of this situation.