When you drive a rover for a while, the solar panels seen to just fall off with no warning. It seems to always be the right panel first followed shortly by the left. There does not seem to be any warning of this in the log and even after they have fallen off, nothing appears in the log tab.
I assume this event is triggered after the rover has travelled for so long. I has happened on two of my rovers so far and only seems to happen on the medium sized rover.
I think that it needs to be more random and they shouldn't fall off after just travelling a certain distance.