It defaults to stretch because the base configuration in live build live config has not been changed by the maintainer. You could file a bug report on it if you want.
On 09/10/2019, p...@gilbertson.biz <p...@gilbertson.biz> wrote: > Thanks Jacek for the help. I typed "lb config --debian-installer live -d > buster" and it worked!! I wonder why it was defaulting to stretch? > > Cheers > >