Hey @akash5 !
This is a known issue where there is a discrepancy with the Estimated BAT counter, see here → Heads up: Estimated pending rewards counter fix
Also if you do not receive the full payment of Estimated Earnings into your Brave wallet, the remainder go over into the next months payout period. This will result in an incorrect reading in how much BAT you actually have accumulated. As long as you are seeing BAT deposit into your wallet during payouts, your wallet is working as intended.
I hope this helped clarify the issue!
Porridge