Libris prize has been awarded 20 times and, there are 20 links to the item for the Libris prize. Sounds good? Actually no. The prize was warded twice to the same person. It appears that there is an issue.. Wikidata:Database reports/Constraint violations/P166
What this amounts to is a lot of well intentioned hand waving. Reports like this are regularly generated and as far as I can tell nobody bothers. My understanding is that it is part of an approach to Wikidata that does not conform to what it is.
Wikidata is by design free of restraints. Reporting constraint violations only make sense when restraints exist and are managed. As these lists are not updated when "constraints" change, they have all been invalidated.