I really don´t know how brave distributes the BAT but i have been traking the earnings today, I initiated with 14.9 BAT and i´m ending the day with 15.4 BAT. For every add that i haved seen i earned 0.5 BAT since i viewed 10 ads in the whole day. Yes i know, you probably do more in one day, but all depends in your region and your search preferences, i´m from mexico, and well i only earn 10 -16 BAT peer month, so if you earn more your lucky.
Seen this you need to remember that BRAVE pays us part of the revenue from the anouncers in BAT, so if there are a lot of users but few campains in your region, well they need to divide the incoming destinated for ads between the number of users, so maybe thats way you have been earning less per add. Anyway it is just a thought that i have to explain the situation on this thread and it´s a bit accurate taking in count the comment of eljuno more if i consider that not all ads pay the same amount of BAT, this because the anouncer declares the amount of money destinated for their ads campain on BRAVE.
Edit: aperently i want to think is a bug on the new version i don’t have my Brave updated to the most recent version. Saying that this other thread explain the same situation