Objectively that is highly highly unlikely for a flight of that nature in the airspace it is in.
Others have given a rundown on the basics but fundamentally it all boils down to Flightradar (and the other tracker sites) simply not having universal worldwide coverage..because there aren't enough amateurs in a region running ground stations and/or they don't have access to the data the mil?ATC have...Amateur covereage is particularly "thin" over remote areas.
So occasionally aircraft go into the gaps and the sites dump them from the display or go into a predictive mode..OTOH behind consoles in the pro world ATC/the mil the watchers may still have access to the transponder data e.g. through satcom or their own receivers...
Rather then trying to inform on secondary radar and ADS 101 I'll offer up this link, which is flight radars own explanation of the issue:
https://www.flightradar24.com/how-it-works