Hello there,
Thanks for reaching out.
This behavior is expected when using Frontend Editing in SP Page Builder. The editor opens in a separate application context, and if the session or authentication cookie is not recognized in the new tab, Joomla asks you to log in again.
Please make sure Joomla allows sessions to be shared between frontend and administrator.
Go to: System > Global Configuration > System
Sample screenshot: https://cleanshot.com/share/7n2l1B2j
Check: Shared Sessions > Yes
Save and test again.
Sample screenshot: https://cleanshot.com/share/h8kBdKmF
Let me know if it helps!
Best regards,