Also confirmed in 4.22 Main @ CL 4413632
Create a level sequence
Add an audio track
Add an audio clip
Right click on the audio clip and set Properties->Sound Volume->DefaultValue to some non 1.0 value (ie. 0.2)
EDIT: In 4.20 Right Clicking clip is no longer a way to access Volume, you must expand audio track to set.
Reopen and check that value.
EDIT: Workaround: Create a Key for volume
Head over to the existing Questions & Answers thread and let us know what's up.