“CGNATs also create significant operational fallout stemming from the fact that hundreds or even thousands of clients can appear to originate from a single IP address,” wrote Cloudflare researchers Vasilis Giotsas and Marwan Fayed. “This means an IP-based security system may inadvertently block or throttle large groups of users as a result of a single user behind the CGNAT engaging in malicious activity.”
https://www.theregister.com/2025/11/03/cloudflare_cgnat_bias_research/