SpaceX has published an explanation for the debris from the Falcon 9 second stage that fell over Poland last week. Because of an oxygen leak, the expected deorbit burn didn't occur.

According to SpaceX, the Falcon 9 first-stage ... 2 mission to the moon between 7:02 p.m. and 8:04 p.m. from Kennedy Space Center Pad 39A. SpaceX pushes launch to end of the window Update 1: ...