Hi, that looks normal to me if you are using the Privileged access (Preview) for PIM enabled groups and the activation time is set to 8 hours.
Once the 8 hour mark is hit, the PIM agent (Initiated by (actor)
will remove the user from the group.
If you creating a role assignable group and making it PIM eligible and not using the Privileged access (Preview) feature, the audit logs wont show that