When CFConfig is used with a Lucee "Light" build, it adds the mapping for the Lucee Admin, making the web administrator available. The Light builds do not have this enabled by default.
As per our Slack discussion, this appears to be coming from the lucee-server-base.xml, which includes the mapping. Removing the mapping from the base XML config resolves the issue for the Light builds and does not appear to impact the standard Lucee builds.
I'll be putting in a PR for this.