Because they know exactly how judgmental this community can be at times, and they were/are actively trying to fix the bug. They knew that as soon as they mentioned a bug had been found people would jump on them and whine, like is happening right now. They probably believed it was possible they'd fix it in time, and then IB could go on without anyone having been riled up in the first place. Imagine what would have happened if they'd said three weeks ago that this IB would be postponed. People would complain, like they are now. And then imagine if they'd fixed the bug and later had to say, oh nevermind, we got it. They'd just invite another round of whining, because that's what this community loves to do. I don't believe for a second the response would be, "Oh great! Thanks for working so hard to fix that!" Instead it would have been, "Typical bungo, can't even get a delay right." You also have to forget what you think you know about the timing. When they say late-breaking it probably means late in their development cycle. We have no idea what that means in calendar days. All they're doing is being honest about the problem.