Parol is a Soviet / Russian system for identification, friend or foe (IFF) and is the successor to Kremnij-2 system. Using cryptographic methods, a much better imitation security is achieved. In the late 1980s, introduction to the East German forces began.
I’d think that planes like that and large SAM systems would have some kind of IFF system active.
Given that it was shortly after takeoff, I wonder if it was some guy with a MANPADS that wouldn’t have had access to that sort or information?
googles
Yeah, sounds like something called “Parol”.
https://www.mil-airfields.de/equipment/soviet-russian-iff-parol.htm
https://youtube.com/watch?v=RKZaxOAWE30