This log entry basically is self explanatory. It triggered 3 times right after setup of ES 10 and firewall, still in progress of Threat Prevention and Web Control
Erik ran McAfee Endpoint which attempted to access /usr/local/McAfee/StatefulFirewall/var/\StatefulFirewallTrace.log in a manner which violates rule 'Core Protection - Protect core McAfee files and folders' and was blocked. (Details: Blocked Write)
So Endpoint Protection is trying to write to log and is prevented to do so by.... Endpoint Protection. Which it probably wants to write to log, but is prevented to so by... etcetc
Thanks for your feedback Erik. We already have a defect logged for this which is in consideration for fix in the upcoming release.
EnSM Beta Team