Can you give us the full details of the problem Clip, and your Sequence settings?
Also, a screen-cap of your Sequence with that Clip showing, and the Program Monitor with what you are encountering, will be very useful.
Treatment of the clip
Info of the clip
My work area's rather messy now. I chopped up pieces (from a main source), and they're all over the place, but since this is the only clip that won't work I find it strange. The whole work area's been rendered as well.
Could I've "overworked" it somehow, "abused" it (since it's been dragged back and fourth, effects applied, effects removed etc)?
Put the Flip on top of the Crop effect, instead of under it.
Didn't work. Instead of turning completely black, this time it just got darker.
OK, I took a shot without testing.
I can't reproduce the behavior, though. Here it just works no matter how I do it.
Try removing all effects, then apply just the Horizontal Flip. What happens?
I'm pretty sure I know what's wrong now. I copy the clip, paste, and when I do the flipping, I flip the whole original image (not just the parts of the image I've resized / scaled. There are parts of the original image that contains, some dark areas, and that's probably what I see. Could've noticed this earlier perhaps, but I'm working with an abstract image, and the shapes are similar throughout.
However, It still sounds weird, because I'm bascially working with two identical clips, why wouldn't it just flip? I want to flip within the positions and degress of my already scaled image, not the whole original one.