A problem with alternate behaviour

Hello!

When two elements point to the same source, the alternate view in a pop-up shows only the first instance in a page. It should show the alternate content always, not just the first time.

We have a text with a critical apparatus in margin notes. We use <app> <lem> and <rdg>. In every <rdg> we show every <witness> as a siglum and a pop-up that shows the complete name of every manuscript. Usually, a lot of manuscripts are the same in every reading. In the note all the sigla appear rigthtly, but it just shows the pop-up with the alternate content the first time a manuscript is cited, not in the subsequent readings or apparatus.

Sorry if I am not able to explain myself better, you can see what happens here:

(http://thebarumfabula.usc.es/exist/apps/bibliotheca/Statius-Thebaid.xml)

Any idea of what is happening?

Thanks for any help!