After running the post timesheet job, you expect that any timesheet on an approved status gets posted.
However, there is a specific timesheet that is not being posted. Why?
Look at the bg-ca.log file to understand what the cause is as those can vary.
See the below list of known KB articles. If a solution is not found here, it's recommended to check further using self-service as this may not be an all-inclusive list.
where prstatus = 3 --approved
See also: Clarity frequently reported issues