When two deployments depend on the same library it could throw and IOException.
The problem is located in

 org.jboss.as.server.deployment.module.descriptor.JBossDeploymentStructureParser12 

• When it is executed in sequence
  1. The first time is called with the argument "path", VFS is using RootFileSystem and it is considered a file.
  2. Once it is called the second time, VFS is using JavaZipFileSystem (is mounted during the first call) and this time is not considered a file.

• When is executed in parallel
  1. both of them are using RootFileSystem. The second time VirtualFile.isFile is called throws an exception (Caused by: java.io.IOException: VFS000017: Filesystem already mounted at mount point)