Why were my AI-generated images rejected while similar ones got accepted?

Machine generated graphics have to be checked for accuracy and good image quality.

To be honest, the AI generated icons I've seen lately, all look similar. I think that's the risk you take when using a service that churns out millions of similar assets for practical use. It's not as important to be unique. 

On the other hand, Stock is a commercial business that wants unique content. They have to please their paying customers.

Make sense?

Have you looked at existing images in the Adobe Stock database? If I search AI images for "key" I get more than 1 million hits. If I search for "red heart" I get more than 3 million hits... These simple images already exist in abundance in the database. That's why they were rejected.

Your images are stuck in Virus scans. Only thing I can tell you from the one I can see is that you should select No when there are no property or recognizable people in your images.

As far as the rejections go, a number of contributors, myself included, are receiving rejections for assets that are too similar to others in the database. This may be true in some cases, but many that are arguably unique are also being rejected as similar despite having no quality issues.