You need to make all your changes in Multitrack View, then go to Edit/Mixdown and select "all audio clips" or "selected audio clips;" CEP will mix to a stereo or mono track (depending on what you tell it to do) in Edit View and all the Volume Envelope and other changes will be preserved.
Simply applying volume envelopes to a track on Multitrack View and then transferring to Edit View does not transfer any changes applied in Multitrack View.
You need to make all your changes in Multitrack View, then go to Edit/Mixdown and select "all audio clips" or "selected audio clips;" CEP will mix to a stereo or mono track (depending on what you tell it to do) in Edit View and all the Volume Envelope and other changes will be preserved.
Simply applying volume envelopes to a track on Multitrack View and then transferring to Edit View does not transfer any changes applied in Multitrack View.