As mentioned before: the radar is currently very limited so don´t jump to conclusions using the current version. There´s some weird theories out here explaining stuff that´s really just "not implemented yet" or simply a bug.
Speaking of the real Radar: There is no "short range filter" dropping contact due to them being "very close". The radar doesn´t loose track of targets travelling co-speed. Ownship maneuvering doesn´t drop locked STT-contacts as long as they remain within the scanned volume of the radar. And so on.
In real life working the radar (air-air) is quite a complex thing, even more so in singleseat fighters. There is a whole lot of coordination going on within a formation as to which radar mode to use when, who scans which part of the sky, sorting, targeting etc. pp. And those "standards" differ between different users/nations of the same radar/weapon system.
Bottom line: wait until this radar is more functional.