If you've not connected your bank account (i.e. given your sort code and account number) you will see padlocks near your minimum bank balance and overdraft settings - this is because you require an active bank connection (Chip needs to read an accurate bank balance) to enable these.

Overdraft settings default to ‘off’, so if Chip cannot read a bank balance this means sometimes you may receive an unwanted save in your overdraft. 

Don’t forget, you have the option to cancel any pending save before 3 pm on the same day!