Lawdog has an interesting viewpoint on it.
Can’t say his scenario is unlikely. IN fact, he may well have hit the nail on the head.
Lots of possibilities. This one is more likely than true sabotage or outright blowing the things up by a nation’s military.
Likely we will never know for sure though.
But if I were in Germany, I’d be buying wool socks and blankets right now. Warm jackets too.