When the AJAX person picker makes a request to search for persons matching a given string, HugeVocabularyJSONView.__call__() calls vocabulary.searchForTerms(). This call can return wrong search results for UserTeamsParticipationVocabulary and UserTeamsParticipationPlusSelfVocabulary, because the method of the base class, NamedSQLObjectHugeVocabulary is used, and this method obviously returns all records of the table Person matching the search term, regardless if they belong into UserTeamsParticipationVocabulary or not.
Kicking to registry because this sounds like a user/team thing, and something they are better equipped to triage.
It also sounds like something that should be changed in the usage of the base class, rather than in the base class itself.
That said, if registry (or bugs?) triages this high but wants Foundations to assist or entirely address, let me know.