When it is a bug in the code there is not much you can do other than be very specific in how you describe the problem and share us the simplest example you have that shows the problem. When that happens ... bugs get fixed fast.
Yea.. what he said. Basically, if we can reproduce the issue in the debugger, things are usually fixed pretty quick. In this case, I just opened your sequence, hit render, saw it "hung", hit "pause" in the debugger and looked at where it was stuck. From there is was fairly quick to figure out what is going on and fix it.
If we cannot reproduce the problem in the debugger, then things are WAY WAY harder and likely not to get fixed.
