CDP polling for Insight should not be scheduled to run more than once an hour max. It is preferred to have CDP run by day part or every 4 hours for CDP.
If you are getting grind processes having issues, then there is a different problem on your POS. The grind process is not gracefully exiting every time and you should start by reviewing the log files to see if you can determine why. The process is designed to handle simultaneous calls without issue. So, when you are having the issue, then that is an indication of another problem.