Thank you for your reply!
I create animations themselves, but the developers have a problem with playing, or rather to the lack of notification of the completion of some animations play. In them I used to change the direction of bending of the kinematic pair.
I'll report your answer to developers, should decide the issue. I'm more worried that this is something I messed up.
Sorry for my clumsy English, if you suddenly do not understand the information presented :$
Answer of developers:
"Hello! We use js version, and they sent a link to c ++. pliz write that we have the latest version of js"
So ... I think it is, nevertheless, the problem of constraints with my animation. :bang: