It looks like resource manager is in action. Your dba configured this most likely to give certain processes priority over other processes. Oracle Scheduler is fuly integrated with Resource Manager but the way this is presented is a bit misleading. Often it has nothing to do with Scheduled Jobs at all.
You can find which sessions are waiting for resource manager by checking v$session:
select sid, serial#, username, resource_consumer_group from v$session
where event like 'resmgr%'
Resource Consumer Group membership of a session determines what priority a session gets. Resource Manager is a very powerful way to manage load on a system to make sure that important processes can finish in their designated time. Maybe your sessions are not mapped to the correct Resource Consumer Group.
Your dba needs good info about business priorities to be able to make a correct Resource Plan.