Our SharePoint 2013 on-premise farm is installed on DomainA.com. DomainA have form one-way trust with DomainB.com. We have setup user profile sync for both domains. But we didn't configure our people picker to handle DomainB.com.
From my understanding, all people picker would not able to query for any users under DomainB. Even I type in correct AD login ID (e.g. DomainB\userA), the people picker should return "No exact match was found".
However, on the same farm, site collection A can add two users DomainB\userA & DomainB\userB. On site collection B, only Domain\userA can be added (userB return no exact match error). On site collection C, both users cannot be added and return No exact match error.
Site collection A and B was migrated from a SharePoint 2010 farm. Site collection C is newly created. The old 2010 farm have been discarded so I cannot check the old settings. Why is it?