1. Create a content item with an image field, add the image in the first version.
2. Edit and republish the item without modifying the image
3. Query the content over REST (curl -v http://localhost:8000/api/ezp/v2/content/binary/images/54 -H 'Accept: application/vnd.ez.api.Content+xml
4. Query twice a variation of that image over REST, using the URI found in the image field value in the response above (curl -v http://localhost:8000/api/ezp/v2/content/binary/images/54-194-1/variations/small
5. On the second request, X-Cache will be a MISS, while we expect a HIT
This is because of the image ID (54-194-1) in the variation request. 1 is the version number. The response is only cached if that version number (1) matches the current version number of the content item (2 with the procedure above). Removing that test fixes the issue.