steps to reproduce:
run mvn cargo:start on a war project with an existing tomcat installation
the war file is copied into the tomcat/webapps directory
run mvn install to create new war file (probably make some changes to notice the change)
run mvn cargo:start
cargo fails to copy the new war file into tomcat and so it's still running the old code.
The only workaround I know is to always run mvn clean before running cargo.