Siebel Server manager tasks getting full

In our environment, we are observing that the server manager component tasks are getting full once in a week. This is causing lot of issue with the performance of the siebel servers.

There is a shell script which runs every hour to check the siebel server status from server manger and reports to us through mail every hour. Not sure if this script is causing this issue.

But, the server manager command are passed from a .txt file and there is a exit at the end of the script too.

May I know what is the reason for this spike in server manager tasks ? Max tasks 20 in our environment.