There are a few places where the ModuleIdentifier.create(String) method is used for module names which could potentially have a slot. This method does not parse the string for slots and simply uses the parameter as the name for the module. A module defined as org.wildfly.core.example:main would end up with a module name of org.wildfly.core.example\:main due to the : being escaped. The ModuleIndentifier.fromString(String) should be used in these cases.