Not sure why but on 3.3.0 a warning is issued when using entrypoint instead of mainclass (and other java friends):

[WARNING] mainClass, extraClasspath, jvmFlags, and expandClasspathDependencies are ignored when entrypoint is specified

Is it possible to lower the level (idea being warning -> requires attention, error -> fails). Here it does not require any intention since it is an explicit user action so it is intentional.