Vaadin 7 to 8 migration - theme problem number 2

I get this problem in my pom file inside eclipse:

Compiling theme "VAADIN\themes\mobiwms" failed (com.vaadin:vaadin-maven-plugin:8.8.2:compile-theme:default:generate-resources)

org.apache.maven.plugin.MojoExecutionException: Compiling theme "VAADIN\themes\mobiwms" failed
	at com.vaadin.integration.maven.CompileThemeMojo.processTheme(CompileThemeMojo.java:69)
	at com.vaadin.integration.maven.AbstractThemeMojo.doExecute(AbstractThemeMojo.java:43)
	at org.codehaus.mojo.gwt.shell.AbstractGwtShellMojo.execute(AbstractGwtShellMojo.java:182)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:331)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.lambda$7(MavenImpl.java:1342)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
	at org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:1341)
	at org.eclipse.m2e.core.project.configurator.MojoExecutionBuildParticipant.build(MojoExecutionBuildParticipant.java:52)
	at com.vaadin.integration.eclipse.maven.VaadinMojoExecutionBuildParticipant.build(VaadinMojoExecutionBuildParticipant.java:87)
	at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:137)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:173)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1$1.call(MavenBuilder.java:116)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1.call(MavenBuilder.java:106)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:177)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:151)
	at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:99)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:87)
	at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:201)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:833)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:220)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:263)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:316)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:319)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:278)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:468)
	at org.eclipse.core.internal.resources.Project$1.run(Project.java:574)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2295)
	at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:548)
	at org.eclipse.core.internal.resources.Project.build(Project.java:116)
	at org.eclipse.jdt.internal.ui.util.CoreUtility$BuildJob.run(CoreUtility.java:162)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: org.codehaus.mojo.gwt.shell.JavaCommandException: Command [[
C:\Program Files\Java\jre1.8.0_171\bin\java -Xmx512M -Xss1024k com.vaadin.sass.SassCompiler D:\tonybaldarelli\Documents\workspaces\eclipse-ide-for-java-ee-developers\vaadinwebsite\src\main\webapp\VAADIN\themes\mobiwms\styles.scss D:\tonybaldarelli\Documents\workspaces\eclipse-ide-for-java-ee-developers\vaadinwebsite\src\main\webapp\VAADIN\themes\mobiwms\styles.css
]] failed with status 1
	at org.codehaus.mojo.gwt.shell.JavaCommand.execute(JavaCommand.java:330)
	at com.vaadin.integration.maven.CompileThemeMojo.processTheme(CompileThemeMojo.java:65)
	... 37 more

This error goes away when I comment out the “compile” goal in the below section of the pom, basically changing <goal>compile</goal> to <!-- <goal>compile</goal> -->:

			<plugin>
				<groupId>com.vaadin</groupId>
				<artifactId>vaadin-maven-plugin</artifactId>
				<version>${vaadin.plugin.version}</version>
				<configuration>
					<extraJvmArgs>-Xmx512M -Xss1024k</extraJvmArgs>
					<webappDirectory>${basedir}/target/classes/VAADIN/widgetsets</webappDirectory>
					<draftCompile>false</draftCompile>
					<compileReport>false</compileReport>
					<style>OBF</style>
					<strict>true</strict>
				</configuration>
				<executions>
					<execution>
						<goals>
							<goal>update-theme</goal>
							<goal>update-widgetset</goal>
							<goal>compile</goal>
							<!-- Comment out compile-theme goal to use on-the-fly theme compilation -->
							<goal>compile-theme</goal>
						</goals>
					</execution>
				</executions>
			</plugin>

So what is happening?

Could this be caused by add-ons that don’t have compatibility modes, and thus reference things that are not supported in Vaadin 8? In other words, a deeper issue is cascading to the issue I am seeing.