Emcli update_db_password in arg file; some jobs hang; "Waiting for Output Log"

Hi

This is EM 12.1.0.2 on rhel 5 x86_64.  The OMS runs on one node of 3-node 11.2.0.4 cluster; the repository database is RAC 11.2.0.2 on the same cluster.  I'm using emcli with an argument file to change the dbsnmp password and the monitoring credentials.  It's the same command for each target.  Two jobs succeeded, and three hang.  The hang up is Step:updatePassword.  The ones that succeed return "No output for this step".  The ones that hang return "Waiting for output log" on the very same step.   What output log?  Why does the same step return different data?  In both successful and running jobs, Step:changeTgtPassword succeeds.