Chase has begun sending out emails to confirm that you have received a bonus. This is being done for almost all types of bonuses at Chase. From this DoC post, looks like they will now send you confirmation when you get a referral bonus, credit card bonus or bank account bonus. It really makes it much easier to keep track of bonuses, especially if you have a few credit cards and maybe bank accounts.
The bank bonus confirmation email is sent a couple of days after the bonus is credited to your account. The referral emails are sent on your statement close date when the bonus points post.