Issue Summary

This is reproducible on Data Center: yes

The Activity Stream is blank for users not authenticated in the external application when using application links configured as OAuth as Local authentication. 

This would be an issue if the users don't have access permission to all the application links configured. 

Dashboard gadget:

User profile gadget:

Steps to Reproduce

1. Install Jira 9.5+ 
2. Create an application link with an Atlassian application like Confluence using OAuth as Local authentication.
   
3. Create a Jira user that only exists in Jira.
4. Log in with this new user and create a comment in a Jira issue to generate some data.
5. Verify the Activity Stream dashboard gadget and the User profile gadget.

Expected Results

Both the Activity Stream dashboard and the User profile gadgets should display data even without the authentication with the external application: 

Actual Results

The Activity Stream is empty.

Workaround

For the Activity Stream dashboard gadget, the user can remove the external application from the gadget filter. 

For the User profile Stream gadget:

Changing the Local authentication to OAuth (impersonation), in the application link configuration, would allow the gadget to load, however, make sure that your instances are following the requirements described in OAuth security for application links before making the change.