This is all very true. When using some of my tech (even the cool ones) there will always be a set of button presses or using them in a certain way that will cause the system to crash or to free or to do something random. This is with alpha testing and potentially beta testing with thousands of users.
I don't see why a plane would be any different. There will always be interactions that can cause a problem. Much like when a teacher's fancy power point presentation won't load or crashes and they have to use a black board to do their job. The Airbus is just the same. It is an all singing all dancing PowerPoint presentation with all of the fancy animation, sound effects and other wizardry people like to dazzle their audience with. However if I want an ole' fashion blackboard then I have that option too.