No news like that has crossed my view. It may be that a blasting material was chosen which would be washed away by the immersion in the ocean. So nobody could know except by suspicion of substances of that kind.
Or it could be that all the “experts” are just assuming all those sensors were sending back valid data. I’ve yet to see even a hint of a discussion about the possibility that the plane was hacked via satellite. Or even by a passenger and his laptop. Malware that can hack cars and pacemakers and insulin pumps is now common knowledge; not the actual knowledge but the fact that it can be done.
Even if this has already happened on airliners, that kind of information would be held as tightly as the Roswell, NM incident. Otherwise, the entire airline industry would collapse overnight. We would never hear about it.