Wrong ad counter, Brave beta android

Past 3 days in noticing this wired issue with my brave beta on my android device. Just for fun, I did not close any ad tabs for a whole day and found that I got 18 ads on the same day. At the start of the day my rewards details (0.520 BAT, total ads revived this month= 49).
Next day morning I checked the rewards details and it was the same. Approx 40 ads in 3 days are just vanished.
I am not sure did this problem exist earlier because I didn’t take a look at the rewards prior to this.