Your browser is likely leaking your IP address, even if connected to a VPN

Browsers support a peer-to-peer API called WebRTC.  Its purpose is to improve user experience with communication applications, however, it leaks your private and public IP address even when connected to a proxy or VPN.

Here's a reference detailing how to disable this functionality for the major browsers, and here is how to disable it in Brave (click "WebRTC IP Handling Policy").

After you fix the problem, check this WebRTC Leak Test tool.  Under "IP Address Detection", you should see "n/a" instead of any IP addresses.

Here's an article by to learn more about the WebRTC flaw.