The German MP717 was pretty powerful I still have those, but it’s more of clout thing especially with the Russian Thompsons. Using it shows your veteran status
it’s too late for my reply, but I can confirm that I lost my super thomsons on my soviets as well. I haven’t played them 'til now and since I decided to try them now I discovered that the weapons that I had from the event are missing.
Of course I tried too to disarm reserves, etc. Although, if you click at the squad it seems from the description that their weapon is the Fedorov Automat. I have 6x fedorov weapons, but i havent’t leveled anything in research, so i guessed that these weapons did replace my thomsons. It seems like the squad has changed, and maybe the bug is with the people that still, have the thomsons.