Yeah after their "re-education" they were returned, in fact a lot of Ukrainian POWs were returned back after a stint in reeducation and they also have to sign documents stating they will never fight again - and if caught again they will be executed etc. 

They Chechen fighters are some of the hardiest motherfuckers around  - they did a lot of progressive work in tight urban areas, Kharkiv, then moved to Mariupol and then to Azovstal.  Followed their "story" from their announcement to their take over of Azovstal.

In fact, I've been following this Ukrainian thing since 2012 or so