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This might not be the reason why the developer chose to have the program essentially pull the fire alarm and go home in this case, but that's the impression I got.
I mentioned elsewhere that any ATC system has to be resilient enough to handle things like in-flight equipment failure, medical emergencies, and the diversion of multiple aircraft on account of bad weather or an incident which shuts down a major airport.
As for why the system "pulled the plug", the author of the article suspects that this particular error was regarded as something that would not occur unless something catastrophic had caused it, whereas, in reality, it affected only one flight and could probably have been easily worked around if the system had informed ATC which flight plan was causing the problem.