I have an estimated 20 BAT showing as AD rewards payout in May. I have had about as much in previous months but all the BAT vanished on payout day and did not end up in my Uphold wallet.
My rewards statement is showing zero BAT for previous months.
I can see no reason why this should happen.
I expect it to happen again in May.
There are com nice fatures in Brave but it feels immature to me and I have had problems with, for example, online banking, that did not occur when I reverted to Firefox (these problems seem to be gone now and most do not persist).