SpaceX launched their third Falcon 1 rocket from Kwajalein Island over the weekend. Hoping to build on their two previous test flights, they carried customer payloads this time … but a longer thrust decay transient of our new Merlin 1C regeneratively cooled engine (by 1.5 seconds!) seems to have produced a small thrust that was just enough to overcome the stage separation pusher impulse.
They plan to put flight four on the launch pad as soon as next month, having integrated, rolled out and launched in seven days. They are confident that they know and understand what happened and can easily work around it.