Comment 3 for bug 1437357

As bug 1454711 shows, it's still possible to make it crash like that if you rapidly tap with many fingers simultaneously on the screen.

You get that in unity8.log:

"""
qtmir.mir.input: Would move a touch that wasn't pressed before (id = 15 ). Making it press instead.
qtmir.mir.input: There's a touch (id = 14 ) missing. Releasing it.
qtmir.mir.input: There's a touch (id = 20 ) missing. Releasing it.
qtmir.mir.input: There's a touch (id = 26 ) missing. Releasing it.
qtmir.mir.input: There's a touch (id = 33 ) missing. Releasing it.
qtmir.mir.input: Would move a touch that wasn't pressed before (id = 36 ). Making it press instead.
qtmir.mir.input: There's a touch (id = 35 ) missing. Releasing it.
terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::logic_error> >'
  what(): Only one touch up/down may be reported per event
"""

So mir is sending incomplete touch streams and qtmir tries to clean them up (filling in the gaps) before dispatching those events to apps. But then it doesn't do such a very good job at it and mir complains, throwing an exception