Fuse 6.2.1 fabric:ensemble-remove raises "Error executing command: String index out of range: -1" on Karaf console

Issue

We are trying to down size our Fabric ensemble using fabric:ensemble-remove.
This however raises

Error executing command: String index out of range: -1

on the Karaf shell and this error in the log file

2016-11-18 18:04:20,105 | ERROR | l Console Thread | Console                          | 38 - org.apache.karaf.shell.console - 2.4.0.redhat-621159 | Exception caught while executing command
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1967)[:1.8.0_60]
    at io.fabric8.commands.EnsembleRemoveAction.applyEnsembleConfiguration(EnsembleRemoveAction.java:121)
    at io.fabric8.commands.EnsembleRemoveAction.doExecute(EnsembleRemoveAction.java:87)
    at org.apache.karaf.shell.console.AbstractAction.execute(AbstractAction.java:33)
    at org.apache.felix.gogo.commands.basic.AbstractCommand.execute(AbstractCommand.java:35)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)[:1.8.0_60]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)[:1.8.0_60]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.8.0_60]
    at java.lang.reflect.Method.invoke(Method.java:497)[:1.8.0_60]
    at org.apache.aries.proxy.impl.ProxyHandler$1.invoke(ProxyHandler.java:54)[19:org.apache.aries.proxy.impl:1.0.5]
    at org.apache.aries.proxy.impl.ProxyHandler.invoke(ProxyHandler.java:119)[19:org.apache.aries.proxy.impl:1.0.5]
    at io.fabric8.commands.$EnsembleRemove2055793643.execute(Unknown Source)[mvn:org.apache.aries.proxy/org.apache.aries.proxy.impl/1.0.5:]
    at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:78)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:92)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.karaf.shell.console.jline.Console.run(Console.java:197)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]
    at org.apache.karaf.shell.console.jline.DelayedStarted.run(DelayedStarted.java:79)[38:org.apache.karaf.shell.console:2.4.0.redhat-621159]