It seems possible that the loud noise heard on the video is the audible report of the same event. 5 seconds later, the tank fails.
However, as I understand it, the in-flight failure was due to acceleration forces, which would be going in the opposite direction to bouyancy. They've put extra effort into checking every single strut since then. and I presume the second stage has been test-fired (and, hence, previously fuelled), like the first.
It's possible it's a related problem, but, from what I've read, the failure seemed to start around the umbilical attachments, which would make them a prime candidate. If it disconnected and started spraying liquid oxygen around, that would have been bad news.