I am affected by this from day one (Librem 13v3, a bit over a year old now). I am running PureOS, keeping it updated, and updating the firmware regularly. Nothing seems to make a difference.
That being said, it now happens much less frequently than during the first weeks.
I still don’t use the laptop regularly, in part because of the fan issue. I did use it constantly during a conference trip for a week, and the fan acted up exactly once.