Brave browser tab loses internet connection after devtools is opened on that tab. This issue only affects the Brave browser in the tab the devtools are opened in. My other browsers (Firefox, etc) and other tabs in the Brave browser do not lose their network connection when this happens.
I just tested on Windows 10 Pro, didn’t seem to happen. I refreshed page by hitting Refresh button icon on Brave, hit F5, and also tried Ctrl R. I refreshed on both tabs and even on different window. Opened dev tools (F12) on just one and refreshed. Then went to other tab, refreshed. Opened dev tools on both, refreshed. Closed on both, refreshed. In all cases, everything worked fine.
The way I could replicate though was if you’ve somehow changed the dev tool to assume you were offline. When you hit F12 to open it, you should have a Network tab. To the right of the box that says Disable Cache there will be a dropdown box. In it, you can set to Offline, Slow 3G, Fast 3G, No Throttling, or Custom. If I switch it to Offline then whenever I open Dev Tools and refresh, it will give me the ERR_INTERNET_DISCONNECTED message, because Dev Tools is telling it I’m offline.
Sorry for the long explanation, but could you check that?