Substring is not found in string

I use bash version 3.2.51(1)

I work with job chains and want to start a new job when the old one is finished. So I check which jobs are currently running and only if the job number of the last run can not be found, a new job is to be submitted.

Here is the part of my script:

    Job_ID=$(msub -E fvcom.pbs)

    # test whether job is still running

    CONTINUE="just started"
    # do this loop, until the CONTINUE variable is empty (i.e. job is finished)
    until [ -z "$CONTINUE" ] ; do
       # wait $WAIT seconds
       sleep $WAIT
       # query if job is still running
       RUNNING=$(./show_my_run)
      echo $RUNNING
      echo $Job_ID 

       # check whether specific job is still running
       # then job ID is present in job overview
       if [[ $RUNNING == *"$Job_ID"* ]] ; then
       CONTINUE="Job_ID found"
       echo $CONTINUE
       else 
       CONTINUE=""
       echo "Job_ID not found"
       fi

    done

The output is:

city.12345/1202110.batch.com kdd046 Running 4 00:59:14 Tue Jul 4
city.12345
Job_ID not found

Obviously I can see that Job_ID is present and the job is still running... The pattern is only recognized if there are several jobs running and the pattern is somewhere in the middle:

city.54321/1202133.batch.com kdd046 Running 4 00:59:14 Tue Jul 4 city.12345/1202110.batch.com kdd046 Running 4 00:56:19 Tue Jul 4
city.12345
Job_ID found

I also tried using

...
if echo "$RUNNING" | grep -q "$Job_ID"; then
...

but with same results.

What am I doing wrong?