Status: resolved. From 13 October, 20:40 UTC until 15 October, 09:22 UTC, a DNS leak test run through our proxies could list extra DNS servers (Cloudflare, located in France, Singapore or the US, wherever our gateway was) next to the DNS of your IP's own ISP.
Why it happened
On 13 October we added a security check to our gateways that stops our proxies from being used to reach private network addresses. To run it, the gateway looked up each destination name with a public DNS resolver, and leak-test sites saw that lookup.
How serious it was
Your real IP was never exposed. The lookups came from our gateway, not from your device, and your traffic always went out through your proxy IP as usual.
What we fixed
Since 15 October, 09:22 UTC, our gateways no longer look up the sites you visit. A DNS leak test now shows only your IP's own ISP DNS, on every proxy, rotating and static. You do not need to change anything. If you want to test it yourself, see the setup guide for the gateway format and run a leak test through your proxy.
Thank you to the customers who reported this to us.