The flight didn't actually disappear, slight misinterpretation of what happened. Some background info: tracks are different colours depending on whether they are under your control (green, called Jurisdiction tracks); going to affect you in some way (blue, called Announced tracks); or in a handoff to or from you (salmon (their wording, not mine!) called Handover In/Out). Tracks that won't concern you are black, not surprisingly called Not Concerned tracks. Tracks turn Blue Announced to you 30 minutes from your airspace boundary, that's how you know something is coming your way.
A side note: the display is a computer generated display based on radar feeds, ADS information and position information entered into the system manually (for those tracks not generating information from those other sources). So, for example, if an aircraft goes out of radar range (which will show on the display as an octagon), it will 'transition' to another track (a different shape) but still show all relevant information.
All aircraft that are receiving an Air Traffic Service should be Blue Announced or Green Jurisdiction. You can only change or interact with the data of an aircraft if you have Jurisdiction. When the service is finished, you can Cancel the aircraft's data, meaning the data is gone for ever, or you can Inhibit the data, meaning the data sits in the background but the aircraft data block is Black Not Concerned. This is particularly handy for VFR aircraft who leave and re-enter CTA at different points and in different sectors. The system will not post Blue Announced tracks to the next sector (stops display cluttering with unnecessary information).
The ATSB report says inadvertently Inhibited. So flight would not post to subsequent sectors but definitely not faded from radar. Holes in the system line up. Definitely a major concern
