This problem could occur if there is an inconsistency in mdb database. Status of a SD activity is still active but its linked SD Job Container is in terminated status (OK or ERROR).
Client Automation 14.0
Execute following SQL Query to find the name of SD Job Container with problem :
select jc.name from usd_job_cont jc, usd_link_jc_act l, usd_activity a
where jc.type=3 and jc.name <>'__SD_Jobs' and jc.state in (6,7,8) and jc.objectid=l.jcont and l.activity=a.objectid
Delete the job container returned by this query in DSM Explorer.