nuxeo-document-attachments incorrect preview links

Studio-side

1. in SETTING / Application Definition
2. in Packages to install ensure Nuxeo Web UI and Nuxeo DAM are present
3. save the project
4. create a custom document type named MyCustomVideo inheriting from Video
5. in Designer configure the view layout with the following code:

   <!--
   `nuxeo-mycustomvideo-view-layout`
   @group Nuxeo UI
   @element nuxeo-mycustomvideo-view-layout
   -->
   <dom-module id="nuxeo-mycustomvideo-view-layout">
     <template>
       <style>
         *[role=widget] {
           padding: 5px;
         }
       </style>
       <nuxeo-document-viewer role="widget" document="[[document]]"></nuxeo-document-viewer>
       <nuxeo-document-attachments role="widget" document="[[document]]"></nuxeo-document-attachments>
   
     </template>
   
     <script>
     Polymer({
       is: 'nuxeo-mycustomvideo-view-layout',
       behaviors: [Nuxeo.LayoutBehavior],
       properties: {
   
         /**
            * @doctype MyCustomVideo
            */
         document: {
           type: Object,
         },
   
       }
     });
     </script>
   </dom-module>
   
   

6. save the project

Server-side

1. install nuxeo 9.10 (not with a later version)
2. install nuxeo-web-ui and nuxeo-dam addons
3. start the server
4. sync the project
5. create a workspace
6. in the workspace create a video document with a main attachment (a video of course)
7. on the right panel attach a 2nd video
8. on the right panel attach a 3rd video
9. wait for the preview to be generated
10. click the preview button (the eye) for the main video
11. observe it is working fine
12. click the preview button (the eye) for the 2nd video
13. observe the preview displayed is the one for the 1st video
14. click the preview button (the eye) for the 3rd video
15. observe the preview displayed is the one for the 1st video

Server-side (bis) - retry the same scenario with Nuxeo 10.10 or master

1. observe each preview is correctly displayed

Expected behavior: each preview button should trigger the display of the right preview and not the one from the main blob.
Note: This works fine with 10.10 and later versions, thus affecting only 9.10. The code has changed between 9.10

      <template is="dom-repeat" items="[[document.properties.files:files]]">
        <nuxeo-document-blob document="[[document]]" xpath="files:files/[[index]]/file"></nuxeo-document-blob>
      </template>

https://github.com/nuxeo/nuxeo-web-ui/blob/9.10/elements/nuxeo-document-attachments/nuxeo-document-attachments.html#L55
and 10.10 :

      <template is="dom-repeat" items="[[_computeFiles(document.*, xpath)]]">
        <nuxeo-document-blob document="[[document]]" xpath="[[_computeBlobXpath(xpath, index)]]"></nuxeo-document-blob>
      </template>

https://github.com/nuxeo/nuxeo-web-ui/blob/10.10/elements/nuxeo-document-attachments/nuxeo-document-attachments.html#L55