You may notice this error when you enable cPGuard WAF, specifically if you are using RUID2. This is a classic bug with RUID2 handler and an official fix is not yet released. To stop appearing this error message in your logs, please do the following steps.
1. Go to WHM >> cPGuard >> Settings >> WAF
2. In the "Whitelisted WAF rules" section, ADD the following rules. This will whitelist the specific rules on the whole server. You need to do it one by one.
3. Save Settings by click on the SUBMIT button