Undeploy never work. Also, it seems the plug-ins doesn't understand well that war file deployed in root will be mapped by Tomcat to ROOT.war because sometime it is very confused.
Maybe the undeploy doesn't work because after calling undeploy the script leave. I mean it seems undeploy is asynchronous so that if the server do not stay UP for a while after undeploy there is no hope it's going to work. This is unmanageable in a scripted environment. Why you don't just delete the uncompressed folder directly?
So some behavior are:
complain cannot find ".war" to be deleted
delete the war but do not delete the folder ROOT or what is inside
deploy the war but do not update what is inside folder ROOT.
It so buggy that I feel I'm the only one on the planet using Tomcat! No kidding.
Configuration like the following doesn't work well at all: