A more sinister explanation would be that evidence of exploitation helped focus attention by each team once it touched them. However, a colleague of Neel Mehta implies that this was an audit-driven discovery without regard to active exploitation (https://news.ycombinator.com/item?id=7558015).

That could still leave the possibility that news of Mehta's discovery leaked, as either a vague hint or as enough info to create larger scans, which then helped tip off the Codenomicon group.

Despite all the reasons for secrecy, non-disclosure, and protection of proprietary methods, I hope each discoverer eventually says more about the steps leading up to discovery.