I don’t think it happened. Even if it happened, the error is likely due to your VPN provider and not with a browser. Use this site to properly check dns leaks https://browserleaks.com/ip. The site you linked did not even work for me, it just keeps saying waiting for results…
I tried this site and I see leaks, probably. I don’t know how to interpret the results.
When I try it on Brave, I see about 20-30 IPs, some of them are from my country. I guess, it is the reason for some content interruptions I see. Some blocked things not getting unblocked properly.
When I try it on another two browsers, I see only one IP. Exactly what I should see.
I use the same extension from very reliable VPN provider.
Odd, it should happen. The error is likely limited to only device/browser. In brave://settings/privacy set WebRTC to 3rd option. On the site I linked, click on ‘Run DNS leak test’.
Also, create a new test profile from top right-hand corner hamburger menu. In this new profile, do not add or change anything. Only add your VPN extension. Again, go to the site I linked and see if your IP/DNS isn’t leaking.