Why send level envelope is not on automation lane while track output volume is?
How do I move an envelope from clip area to automation lane?
 
 
 

Try changing the Edit Filter to Clips and add an automation lane.

Quick way - click on the edit filter menu under the track name (which currently says "BgRvrbSnd") and select "clips." 
 
Because it's currently set to your send, that means the send envelope will be drawn on the track. If you put it back to "clips" which is the default, the envelope will move to an automation lane. 

Beaten by seconds, lol
 

Thanks guys, problem solved! :)