FishEye is missing diffs for files modified on a tag

Steps to reproduce:

Current revision in subversion = 12000+

1. Let fisheye index from a specific revision, let's say 9000.
2. svn copy from the trunk to a tag. This will be revision 12125. (Screenshot 1)
3. Commit a change into a file of the tag. This will be revision 12227. (Screenshot 2). Note: This file is not newly added, but modified!
4. Browse fisheye source to this changed file. Hit the diff link on revision screen (Screenshot 3)

Expected: A diff link, providing a diff between revision 12125 & 12227
Actual: No diff link present

5. Commit yet another change to the same file in the same tag. This will be revision 12259

Expected: Diff between revision 12227 & 12259
Actual: Revision/Activity (tab) screen is shown again.

6. Browse to the source towards the changed file, view revision tab (Screenshot 4)

Expected: Commit of file seen in revision tab (revision 12125 & 12227)
Actual: Revision of file is missing!