If you refer below article, you will understand that to avoid this error to log in /var/log/ltm, we modify the log severity to critical.
This will result in this error not showing at all in /var/log/ltm.
Now, the client has a specific requirement that they don't want this log to completely diminish but set a log count limit. So say this log can be seen 60 times or n times in 1 min.
I myself tried many things but dont think it is possible.
But before concluding thought to give a last try here.