You may want to check to see if you are leaking a local DNS IP lookup address from your provider. I normally use these two sites to test if they are picking up that I am using a remote VPN: https://whoer.net/ and https://www.doileak.com/
If you are leaking DNS info, take a look at your router’s MORE SETTINGS menu, and under Custom DNS Server, try Overriding DNS for all clients, and turning on DNS over TLS.