Description
What type of issue is this?
Question
What SharePoint development model, framework, SDK or API is this about?
SharePoint CSOM
Target SharePoint environment
SharePoint Online
What browser(s) / client(s) have you tested
- 💥 Internet Explorer
- 💥 Microsoft Edge
- 💥 Google Chrome
- 💥 FireFox
- 💥 Safari
- mobile (iOS/iPadOS)
- mobile (Android)
- not applicable
- other (enter in the "Additional environment details" area below)
Additional environment details
No response
Issue description
I have an in-house developed People Picker that uses the clientPeoplePickerSearchUser() API to query users.
For several years, I have had a test process that runs daily to test this People Picker by searching for certain search terms and verifying the results.
About 5 days ago, those tests started failing. Upon further inspection, I found that the API is returning an empty result set when I search for certain users by first name. To the best of my knowledge, none of these users have had any recent change to their profile data, they have a First Name value and a Display Name (which includes the first name) in their profile data, and I am able to search for them by last name or username.
I am also able to find other users by first name.
I have also observed that I get the expected results if I change the search to use UseSubstrateSearch: true and use the same search terms that are currently returning empty results without that option.
What could be the cause of this sudden change in behavior? What can I do to troubleshoot it?