https://bugs.freedesktop.org/show_bug.cgi?id=93341
--- Comment #6 from Jean-François Fortin Tam nekohayo@gmail.com --- For what it's like, compared to my previous comment #5, tonight (same machine, same distro/stack) I was able to trigger the bug pretty frequently by using the Epiphany browser with a particular website—twice within the span of fifteen minutes or so.
So while there is a simple time component (ex: crashes while the computer isn't doing anything in particular), it can also sometimes be triggered by stressing the graphic card a little with some operations (such as can be seen on some browsers).