joblist fills with scheduled job

Hi,
I have a script that cycles the sniffer every 10 minutes which looks like this :

/system scheduler
add interval=10m name=Dumpcap on-event=":local timestamp [/system clock get date] \r\
    \n:local DAY [ :pick \$timestamp 4 6 ]\r\
    \n:local timestamp [/system clock get time] \r\
    \n:local HR [ :pick \$timestamp 0 2 ]\r\
    \n:local timestamp [/system clock get time] \r\
    \n:local MN [ :pick \$timestamp 3 5 ]\r\
    \n\r\
    \n/tool sniffer stop\r\
    \n# 1Gb file\r\
    \n/tool sniffer set file-limit=125000\r\
    \n/tool sniffer set file-name=\"disk1/\$DAY-\$HR\$MN.pcap\";\r\
    \n/tool sniffer quick interface=ether1\r\
    \n\r\
    \n/tool sniffer start\r\
    \n" policy=\
    ftp,reboot,read,write,policy,test,password,sniff,sensitive,romon \
    start-date=mar/08/2017 start-time=00:00:00

It does what i want it to do (the trace starts and stops growing after 10 minutes) but if i check the job list

 /system script job  print 
 # SCRIPT                                                       OWNER                                                      STARTED             
 0                                                              admin                                                     mar/09/2017 08:30:00
 1                                                              admin                                                     mar/09/2017 08:40:00
 2                                                              admin                                                     mar/09/2017 08:50:00
 3                                                              admin                                                     mar/09/2017 09:00:00

it seems like the script get started but never ends.
I tried this on a hEX as well as an i386, both running 6.38.4. did i overlook anything ?