I am not entirely surprised. Around my place, we have a lot of issues with fires started in untrimmed or poorly trimmed trees tangling in power lines here, and it is particularly dangerous after windstorms. In many cases people have been calling to report a problem for years, but nothing can be done. The power company is the only one who can legally handle such trees, and they aren't training or paying enough labor to do the entire amount of the job in any given year, there's a huge well-known backlog. (Ask your local fire services...) The company's tree crews get to it as they have the assigned personnel to do so. Some of those wildfires have been caused by these tangles.
In my own neighborhood we've had two fires of that sort, and another from failure of a PCB-containing box up on a pole.
So I'm not at all surprised to learn there might also be situations where ground faults can happen, not even talking about about bad weather conditions (like salted ice) contributing to the issue.
This is another example of what is meant when people say that we haven't been investing in infrastructure maintenance.