The only remotely possible cause for the error is this whitelist rule: /cookie-law-info/js/cookielawinfo.js. The matching condition is .info, but if for some reason your server is interpreting the dot as match anything then that would explain the false error. Edit that whitelist rule and change it to this below and do all of the manual Plugin Firewall setup steps.
/cookie-law-info/js/(.*).js
And if that whitelist rule does not work then try this one:
/cookie-law-(.*)/js/(.*).js