Same thing has happened to me several times. Once in a while, it’ll switch back to the groups, but then randomly goes back to that list view. I really like the tab grouping, but chrome is so ad riddled and slow, I don’t want to switch back.
open the page in the browser: “chrome://flags/”
search for “Tab Groups Continuation”
change the status to “Enabled Low-end & Accessibility Grid or List support” and click “relaunch”.
now change to “Enabled Low-end device support” and again “relaunch”.
Then I see the tabs in groups but unfortunately this only works for a short time. For some reason after a short time the list view is shown again.
EDIT:
If the tabs are displayed in groups, there is only one small thing to consider, so that Brave does not switch back to the list view…
Create a group: first open a new tab and then a new “tab in group”.
This has been working for me for a few weeks now.
It’s just a shame that none of the developers have offered support.