After some tests, I see that the problem happens when "Sprite" (from the example) is a family instead of an object.
And another thing I noticed is when you "start" a timer with 0ms, the game crashes. Surely no one would need a timer with 0ms, but maybe the lenght is in function of something else and if it becomes zero the crash can happen. We could also test if it's zero and don't try to start, but...