While the mag release paddle not coming all the way back could be an issue, I have many mags that work but don’t allow the paddle to return fully to the trigger guard. I posted a video discussing it on this thread.
What mags are you running? - PSA Products / KS-47 - Palmetto State Armory | Forum
It’s titled “Pondering the Mag Release on my KS-47”. I’m not saying it’s not the problem, just that it’s not always a problem. I know there is a recent video on YouTube of a new KS-47 owner having a similar problem. I didn’t watch all the video, but it he appears to have rectified the problem in follow up videos. Hope you figure it out.