Plugin dependency version change not recognized

Overview

I think I may have stumbled across a bug in Grails plugin dependency management with grails.project.dependency.resolution in BuildConfig.groovy.

We have a Grails app (our-app) and a plugin (our-plugin). We have this in our-app BuildConfig.groovy:

plugins {
runtime "org.grails.plugins:our-plugin:0.1"
}

We run 'grails run-app' or 'grails war' and it picks up the plugin dependency like we expect. The problem comes when we move to a new version of the plugin:

plugins {
runtime "org.grails.plugins:our-plugin:0.2-SNAPSHOT"
}

Now when we do 'grails run-app' or 'grails war', it still picks up the 0.1 version of our-plugin. We look in .grails/1.3.6/projects/our-app/plugins and still see our-plugin-0.1. We can work around this by removing this directory prior to running 'grails run-app' or 'grails war', but it seems like something Grails should be handling.

Steps to recreate with attached Grails app and plugin:

our-plugin

set Artifactory server in BuildConfig.groovy, change <artifactory server CHANGE ME> to your server
set version to 0.1 in OurPluginGrailsPlugin.groovy:

    // the plugin version
    def version = "0.1"

grails package-plugin
grails maven-deploy --repository=artifactoryRelease

our-app

set Artifactory server in BuildConfig.groovy, change <artifactory server CHANGE ME> to your server
set plugin dependency in BuildConfig.groovy:

    plugins {
        runtime "org.grails.plugins:our-plugin:0.1"
    }

grails run-app

With a browser, view
http://localhost:8080/our-app/
See:
Installed Plugins
ourPlugin - 0.1

our-plugin

set version to 0.2-SNAPSHOT in OurPluginGrailsPlugin.groovy:

    // the plugin version
    def version = "0.2-SNAPSHOT"

grails package-plugin
grails maven-deploy --repository=artifactorySnapshot

our-app

set plugin dependency in BuildConfig.groovy:

    plugins {
        runtime "org.grails.plugins:our-plugin:0.2-SNAPSHOT"
    }

grails run-app

With a browser, view
http://localhost:8080/our-app/
See:
Installed Plugins
ourPlugin - 0.1 (!!! Should be 0.2-SNAPSHOT !!!)

NOTE:

.grails/1.3.6/projects/our-app/plugins/our-plugin-0.1 does not get changed to our-plugin-0.2-SNAPSHOT. A workaround for the problem is to delete .grails/1.3.6/projects/our-app/plugins/our-plugin-0.1 before 'grails run-app'.

This problem did not occur when moving from 0.2-SNAPSHOT to 0.2, or from 0.2 directly to 0.3, so there must be something going on with the way Grails is recognizing a plugin dependency version change when there is a non-numeric tag.