Actually, if the Distort - Aspect Ratio is -33.33, then it's my bad -- it's likely to be the other way around. You have clips incorrectly set to Anamorphic 16:9 and your Sequence is not. Select the clips, then go into the Anamorphic column in the Browser, CONTROL-click and choose No to remove the Anamorphic flag from the clips.
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