Yikes, wish I had seen the posts about the A9 Background HIT's. Got 156 rejections from them on HIT'S I did yesterday (February 7th). I've also been blocked from doing the batches they have posted today.
The reason on all the rejections was 'Image Loaded'. They had an option that said "Can't determine background" (forget exact wording) / "Image Didn't Load".
So for items like rugs that also had a small area (about the size of a pencil eraser) showing, I selected that option as there was not enough background to determine whether it was a solid colored background or was in a room/outdoors/etc. I contacted them about a hour ago, but I don't have any hopes on getting the rejections overturned. Hopefully, they will at least separate them into two options instead of just one if they post any more batches for others who want to risk it.