When used multiple times in the same form, one AttachmentSelector uploading a new file set that file value for every other AttachmentSelector on the form.

Reproduction steps

The issue was detected from XCAROUSEL-16, so I'll use that extension here as it's easier to set-up.

1. Install extension XCarousel 1.4
2. Go to XCarousel space
3. Add a new entry
4. In the edition, open Slide 1 part and click "Choose an attachment"
5. Select an image file which is not already uploaded to the current page
6. Click "Upload and select"
7. Repeat step 4 to 6 for Slide 2 and 3, with other image file
8. Click "Save & View" to close the edit mode and go back to view mode
9. At this state, you can view correctly the created carousel
10. Re-edit it
11. Change slide 1 image, with a new one which has not been uploaded to this page already.
12. "Upload and select" and "Save & View"

Result

Every slide now uses the same image uploaded for step 11, because all the values for AttachmentSelector have been set to use it.

Expected result

Only slide 1 should use the image uploaded in step 11. Other AttachmentSelector shouldn't have their value updated.