Why spacecmd fails with 500 Internal Server Error when trying to clone channel tree on Red Hat Satellite?

Issue

• Why spacecmd fails with 500 Internal Server Error when trying to clone channel tree on Red Hat Satellite?

  # spacecmd -- softwarechannel_clonetree;
  INFO: Connected to https://localhost/rpc/api as admin
  Source Channels:
  rhel-x86_64-server-6
  Select source channel: rhel-x86_64-server-6
  Prefix: test-
  
  Copy source channel GPG details? [y/N]: y
  Original State (No Errata) [y/N]: N
  INFO: Cloning rhel-x86_64-server-6 as test-rhel-x86_64-server-6
  ERROR: <ProtocolError for localhost/rpc/api: 500 Internal Server Error>
  

• Entries from logs:

  2015-05-05 11:02:54,066 [TP-Processor8] WARN  org.hibernate.util.JDBCExceptionReporter - SQL Error: 1, SQLState: 23000
  2015-05-05 11:02:54,067 [TP-Processor8] ERROR org.hibernate.util.JDBCExceptionReporter - ORA-00001: unique constraint (RHNSAT.RHN_CHANNEL_LABEL_UQ) violated
  2015-05-05 11:02:54,068 [TP-Processor8] ERROR org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
  [...]
  java.sql.SQLException: ORA-00001: unique constraint (RHNSAT.RHN_CHANNEL_LABEL_UQ) violated
  at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
      at oracle.jdbc.driver.T2CConnection.checkError(T2CConnection.java:676)
      at oracle.jdbc.driver.T2CConnection.checkError(T2CConnection.java:602)
      at oracle.jdbc.driver.T2CPreparedStatement.executeForDescribe(T2CPreparedStatement.java:571)
      at oracle.jdbc.driver.T2CPreparedStatement.executeForRows(T2CPreparedStatement.java:764)
      at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1190)
      at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3370)
      at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:3454)
      at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:79)
      at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:46)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2265)
      ... 31 more