They put themselves in there, when you cut or paste something, you always have to check the Nodes have not got a check on them in the copy paste window. It is a pain in the ?*$ !
Watch this video, we need clip base nodes this is how they should work, we only need the track base nodes for volume automation, that can been done in the mixer. There should be a Pan also.

Envelopes Vol Pan.mp4
Envelopes Vol Pan.wmv