Chuck, If you open the automation lane, for whatever reason, a volume envelope is created.
At least on my (latest) version of Plat. Which locks whatever level you have set.
I haven't really studied how the envelopes work in Plat. So, I was just looking in the lanes to see what envelopes I had on some tracks (from 8.53 projects). (delay/verb send levels etc).
I'm not clear if any envelopes are automatically placed in those lanes.
But, yea, volume envelopes are created automatically unfortunately.