Reproduction

1. Have a carousel already set-up with 3 slides, each with a different image
2. Edit that carousel
3. On the first slide, click "Select an attachment"
4. Browse to a new image (different from the 3 others), and select it
5. Click "Upload and select"
6. Save the page and close edition

Result

All the 3 slides display the image uploaded at step 4.

Expected result

Slide 1 should have the newly uploaded image from step 4. Slide 2 and slide 3's images shouldn't have been changed.

Additional note

This issue doesn't happen when selecting an already uploaded image.

Workaround

Upload the new image, and for every other slide select again the proper image (even if the preview displays the right one)