The only thing I can think of is to check to make sure you’re exporting it in the proper definition. Where did those letters come from, an AE composition? If that’s the case, check to make sure the framerates match up from your AE composition and the Premier sequence. Also, if you’re exporting it in HD, if you’re exporting it in 1080p try 1080i instead, or vice versa. That’s about all I can think of.