With Maven 3.3 the mvn.bat has been renamed to mvn.cmd. In Maven Invoker the mavenExecutable should support both extensions for Windows.
Cannot run invoker ITs on Windows with Maven 3.3.1
Goal integration-test of maven-archetype-plugin fails with 'Cannot run additions goals." in version 3.3.1
release:prepare fails on Windows since Maven-3.3.x