This article explains the behavior observed when installing a new license on a Junos device that already has an active or unexpired license.

This behavior is expected in Junos.

 

When a new license is installed while an existing license is still valid, the system continues to use the current active license until it approaches expiry. 

 

The newly installed license does not immediately override the active one; instead, it is kept in a pending state. The new license will automatically become active one day before the current license expires, at which point the expiry date will update accordingly.

 

No manual intervention is required.