Nothing immediately springs to my mind but I don't think rendering would make much of a difference here. I guess something strange has got in there somewhere and if I were you, in these specific circumstances, I'd now try exporting the first 20 minutes. If that's OK try the next 20 minutes and so on. If the problem is also in the first 20 mins then try exporting 10 minutes and see what happens. Just an idea.. If nothing else it makes for a fun Saturday night :-)
You might also want to share some more details concerning the Sequence involved.