I'm not sure its about this but some days ago i noticed that two old games of mine on kongregate(jimmy poo and ten levels) freezed when I did any input showing a similar error.
I just re-exported the games with the latest c2 build and this solved the problem..
you can see the difference here:
Jimmy poo on scirra arcade, old version, it freezes when you click any input:
Jimmy poo on kongregate, re-exported version, works: