In JFBConnect v6.4, we upgraded to using Graph API v2.3 all the time now. What you're seeing looks to be a bug that was just opened by another user on Facebook's bug tracker:
developers.facebook.com/bugs/661910477277691/
They describe that, on Android devices, the 'old' comment box looks to be used.. which is exactly what you are experiencing.
I'd recommend leaving a comment there and clicking the "Subscribe" button to make sure they know other sites are seeing this problem.
I hope that helps, and please let us know how it goes.
Thanks,
Alex