Yeah, it’s definitely very rare. I can’t seem to find that article right now, but I remember reading that these events account for something like 0.1–0.3% of all wildfires. So while insignificant as an actual cause in general, with 100k+ wildfires happening each year it means that a couple of hundreds per year should still be caused by those. Which is still like one every 1-2 days on average.

Not enough to be a noticeable threat, but enough to cause a pedantic comment mentioning those as existing :)