Datasource not syncing correctly for a team member

I added a datasource to Team forms and used the SharePoint datasource as one of the fields. I am able to search the dropdown of an item. However a team member sometimes searches for an item and would not find it. I have to manually resync the datasource in his settings to have the records update. What might be the issue that cause it? Because i always have an updated record in my setting without the need to manually resync while he does not.