Odd error after running a gatling-it:test using the SBT plugin

It looks like I may have found the problem, and it may be a bug in either SBT or the plugin.

Launching from the command line fails:

sbt gatling-it:testOnly com.example.testApp.ProveItWorks

Launching from the sbt shell works

sbt

gatling-it:testOnly com.example.testApp.ProveItWorks

If it helps to debug the issue, my code is checked in here: GitHub - JohnArrowwood/gatling-sbt-seed: Gatling starter project, with all my favorite helper classes