Yep. These Playstation aeroplanes are all very well until the electrickery starts playing up in unexpected ways. There's always the worry of something in there that the systems designers hadn't thought of.
Good job it was an experienced pilot who could fly using the horizon as his reference. One worries about the capabilities of pilots reared on glass cockpits when they have to revert to basics. (OK, so I eggagerate, but you get my drift.)
Something caused this. Find out what. The mechanics......sorry.....engineers much used "Tested satis, no fault found" isn't good enough.