monitor traffic is specific to the session from which it is run. So, if you duplicate ssh session to your device, and run monitor traffic on one of them, you will not see the packets on the other session.
So, monitor traffic... is not something that is saved in the config. Once your SSH session broke, the capture stopped. In case, you wish to start capturing again, you will need to issue the command once more, of course keeping in mind the impact it can have on your ssh session.
PS: Please accept my response as solution if it answers you query, kudos are appreciated too!
'user@switch> monitor list' shows the files that you are monitoring, this is helpful when you want to see the log messages appear in the current session you are connected.
for example you could use " > monitor start messages " and the file 'messages' located in the /var/log directory will show its messages in the session output, you would then stop this behavior by using 'monitor stop filename'