You're welcome.
If you want to fix the problem, we need to get into that. The changes I suggested should work if the script starts the batch script and waits for it to complete. If you would have shown us the trace output produced by /usr/bin/sh -x, we might be able to give you a definitive answer; without seeing that output or seeing what is in /usr/script8/batch/bat_fstsi61c.sh, we can only make wilde guesses (like I did before).

If /usr/script8/batch/bat_fstsi61c.sh is the batch script and it doesn't return until it is killed, what I suggested should work. If /usr/script8/batch/bat_fstsi61c.sh asynchronously starts the batch script and returns without waiting for it to complete, what I suggested will not work. In that case you'll need to rerun the ps pipeline to reset pid after the batch process is restarted. You wait 20 seconds after /usr/script8/batch/bat_fstsi61c.sh returns (if it returns) before saving $pid in your log file, but you haven't reset pid so you know it has to be an empty string whether or not the batch script restarted successfully.
There are two scripts. You are talking as though there is only one. Until you understand that there are two and how they interact, we're lost. If you actually mean that the script above is the contents of /usr/script8/batch/bat_fstsi61c.sh, then your description of what is going on is extremely confusing and could be rewritten in a much simpler fashion.
If the script isn't ending when it restarts the batch process, my guess still fits the data you're seeing. But until you show us the trace output you got from running this script or show us the contents of /usr/script8/batch/bat_fstsi61c.sh, we are just guessing.