A friend and I took turns locking eachother with the MiG-21 radar. When I was behind him, in search mode, his RWR indicated a lock (constant tone and constantly lit 'eyes'). When I locked him, his RWR stayed this way. When I unlocked, turned off my radar and even broke away, his RWR still indicated a lock. Mine did the same. Cycling RWR power on and off did not help, so we had to mute them in the end.
Thus, maybe two bugs: inability to distinguish between lock and search, and RWR not understanding when lock has ceased, even after there are no possible radar contacts in the vicinity and power to RWR has been cycled on and off.
Of course, it could be the radar being bugged instead.