From what I could gather from the commentary, they were pushing the limits of the booster's control capability. But the booster exploded on engine ignition. The

From what I could gather from the commentary, they were pushing the limits of the booster's control capability. But the booster exploded on engine ignition. They are separate aspects, though they may be related. The commentators also sounded like they were not expecting a failure at that stage. So, concerns may be warranted.