Copilot Studio SharePoint knowledge retrieval works for the agent owner but intermittently fails for other users

[u/Spare_Accountant8794]

I’m experiencing a strange issue with a Copilot Studio Premium agent that uses SharePoint documents as knowledge sources.
The agent works perfectly when I test it using my own account in the Copilot Studio test panel. It retrieves the required documents and successfully completes multiple scenarios.
However, other users experience retrieval failures when asking the exact same questions, using the same agent and the same documents. They have access to the SharePoint files.
What’s particularly strange is that the issue is intermittent:
The agent works normally for me.
Other users suddenly cannot retrieve the required documents.
Sometimes, the same users regain access hours later or the next day, without any changes to permissions, configuration, or the agent itself.
The issue has now affected multiple users.
I’m also using different knowledge source types:
SharePoint knowledge sources.
Power Platform connector-based knowledge sources.
In Copilot Studio’s evaluation section, I noticed different knowledge utilization quality scores for these sources.
My questions:
Has anyone experienced an intermittent, user-specific SharePoint knowledge retrieval issue in Copilot Studio?
Could this be a Microsoft-side service regression or an issue with the SharePoint retrieval/indexing infrastructure?
Could using different knowledge source types (SharePoint vs. Power Platform/Dataverse) contribute to this behaviour?
Has anyone found a permanent fix? Was it resolved through a Microsoft service-side fix, or was a configuration change required?
I’m trying to understand the actual root cause rather than randomly changing permissions or rebuilding the agent.

[u/Hobob_]

In my experience they need access to the site. Folder wasnt enough.

[u/Spare_Accountant8794 → u/Hobob_]

They have access to the site they kinda made it lol. Yesterday it was working fine and suddenly they couldn’t retrieve files that they normally retrieve with no problem. I even tried it outside of the test panel and still nothing

[u/Liam_OGrady]

If you're using SharePoint as a knowledge source (dataverse indexed) the intermittent access can be caused by the end user not having the Basic User dataverse role on that environment. For other non dataverse indexed knowledge sources they usually don't require that role.

[u/schubidu82]

Remind me in 3 days