Bat rewards setting is set to auto contribute turned on without my permission

Bat rewards setting is set to auto contribute turned on without my permission after the brave browser auto update is completed.

Now I lose 1 bat for all my wallets to auto contribution.

Can I have the bat back ?

It is turned on by default. You have to manually turn it off separately on all linked devices. No, you will not get the BAT back, but you can stop it from happening again. Just be sure to check after every update because it may turn back on.