Cannot use the object editor when edit existing changes of a CR

Reproduction steps:
  - Create a document (v1.1)
  - Edit the document and create a change request from that edition

• Go to the change request, in file changes tab and click on "Edit" link in the livetable
• Edit the URL to add "&editor=object" to use the object editor
• Add a new object (such as a ChangeRequest.Code.ApproversClass xobject)
• Put a value to the object fields
• Click on "Save as change request"

Expected results:

• the changes are properly saved

Obtained result:

• an error is displayed in the editor, the modal opens to try saving again the CR
• the following stack trace appears in the console:

  org.xwiki.contrib.changerequest.ChangeRequestException: Cannot find file change with version [filechange-1.1]
  	at org.xwiki.contrib.changerequest.internal.handlers.AbstractChangeRequestActionHandler.prepareDocument(AbstractChangeRequestActionHandler.java:211)
  	at org.xwiki.contrib.changerequest.internal.handlers.AddChangesChangeRequestHandler.handle(AddChangesChangeRequestHandler.java:88)
  	at org.xwiki.contrib.changerequest.internal.handlers.ChangeRequestResourceHandler.handle(ChangeRequestResourceHandler.java:139)