SharePlex internal tables involved in tracking the job ids have residual entries that are causing the 'show compare' output to return a compare job that is not running anymore.
The simplest way to clean it is to issue the following command on Source:
sp_ctrl> clear history <job_id>
In the above example, the job id is 253 for the compare job that does not exist, hence we will issue the following on Source:
sp_ctrl> clear history 253
This would clean up the entries for the specific job from SharePlex and no defunct compare will show up anymore.
In the process it would also remove the logs for the problem job.
Another option is to clear the job history for all the jobs as below:
sp_ctrl> clear history all
But this can have ramifications in that it would clear the history for all jobs and not just the problem job.
The above also applies to a defunct repair or copy job.
Please see SharePlex Reference Guide for more details on the command 'clear history'.