@benoit.lallemand. Thanks for posting. That is quite interesting! Now that I think about it, I understand why it is happening. The index to uniquely identify the listing is locally set for each article. So, it starts a zero for every article. If you have multiple articles, you will end up with duplicate ids for the listings.
To circumvent this, I would have to add an “offset id” parameter for the listing instance, which would offset the id by a certain amount in a particular article. I will have to add that for the next release.