Internal Server Error when changing system child channel of Red Hat Satellite sub organization

Issue

• When unsubscribing a child channel from a system in a sub organization, an Internal Server Error (ISE) is thrown in the Red Hat Satellite WebUI
• Tomcat logs show the following error:

com.redhat.rhn.frontend.xmlrpc.InvalidChannelException: Invalid channel
    at com.redhat.rhn.manager.system.UpdateChildChannelsCommand.unsubscribeFromOldChannels(UpdateChildChannelsCommand.java:188)
    at com.redhat.rhn.manager.system.UpdateChildChannelsCommand.store(UpdateChildChannelsCommand.java:106)
    at com.redhat.rhn.frontend.action.systems.sdc.SystemChannelsAction.updateChildChannels(SystemChannelsAction.java:321)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:60)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
    at java.lang.reflect.Method.invoke(Method.java:611)
    at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
    at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
    at org.apache.struts.actions.LookupDispatchAction.execute(LookupDispatchAction.java:146)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)