Hmmm, tough to say really. Any chance you can post a screen grab of your presets?
It might help to see what the queue is looking like. Sometimes the presets can get messed up and don’t reflect the same settings as the render queue. I don’t know about you, but i’ve seen it happen before.
It’s likely something in the original footage triggering this as you’ve said, but without a screen grab its like shooting in the dark.
-Roger