After creating page with REST and attachment, attachment is lost

Summary

When creating a page via a REST call, if the storage format has an attachment, then that attachment is lost on subsequent edits of the page via the UI, even though it displays correctly on first view.

Steps to Reproduce

1. Create a page via REST call with an embedded attachment (here, an image)
   create page

   curl -s -u admin:admin -H 'Content-Type: application/json' -d '{"type":"page","title":"my page","space":{"key":"KEY"},"body":{"storage":{"value":"<p>This is a new page</p><p><ac:image ac:thumbnail=\"true\" ac:height=\"250\"><ri:attachment ri:filename=\"meeple.png\" /></ac:image></p>","representation":"storage"}}}' http://localhost:8090/rest/api/content/
   

1. Upload the attachment (change page id as required)
   upload attachment

   curl -s -u admin:admin -H "X-Atlassian-Token: no-check" -F "file=@meeple.png" -F "comment=this is my meeple" "http://localhost:8090/rest/api/content/327714/child/attachment"

1. Edit the page through the browser to make a change.

Expected Results

The image stays attached to the page and displays correctly.

Actual Results

The image appears as a Broken Attachment both in view and edit

actual.png

Workaround

Create the page with dummy content, upload the attachment and then update the page with the correct content.

curl -s -u admin:admin -H 'Content-Type: application/json' -d '{"type":"page","title":"my page","space":{"key":"KEY"},"body":{"storage":{"value":"<p>This is a page holder</p>","representation":"storage"}}}' http://localhost:8090/rest/api/content/

curl -s -u admin:admin -H "X-Atlassian-Token: no-check" -F "file=@meeple.png" -F "comment=this is my meeple" "http://localhost:8090/rest/api/content/327714/child/attachment"

curl -s -u admin:admin -X PUT -H 'Content-Type: application/json' -d '{"id":"327714","type":"page","title":"my page",
"body":{"storage":{"value":
"<p>This is a new page</p><p><ac:image ac:thumbnail=\"true\" ac:height=\"250\"><ri:attachment ri:filename=\"meeple.png\" /></ac:image></p>","representation":"storage"}},"version":{"number":2}}' http://localhost:8090/rest/api/content/327714