An ATM deposit, and since most ATMs will not scan or OCR the check, is subject to verification with regards to the date, amount, payee name and proper endorsements. However, most banks -at their option- may either reject or negotiate a post dated check as if it has the current/past date on it.
Since most "post dated" checks are written due to the account they are drawn on not having sufficient funds to cover it, depositing a check before its intended written date is more likely to result in it being returned for insufficient funds. Since banks charge an often exorbitant fee for a bounced checks, it is in their best interest to process it, let it bounce and charge the fee instead of rejecting it. In fact this outcome is unavoidable if the check is processed by way of an automatic deposit (versus it being presented at the bank it is was issued against).
A "check" is a negotiable instrument intended for immediate negotiating, NOT as a promissory note). One should also keep in mind that, in some jurisdictions, writing a post dated check and if it were to arrive at the issuing bank earlier than it was dated for, and assuming the account it was drawn on has insufficient funds to pay the full amount, it can be subject to a criminal investigation and possible charges being filed by locale law enforcement.
A typical Bank Deposit/Account Agreement will have terms that are worded similar to:
If a postdated check — a check dated in the future — is presented for
payment, we may pay the check and charge it to your account even if it is presented for
payment before the date stated on the check. If you do not want us to pay a stale-dated
or postdated check, you must place a stop payment order on it.
So the only way to ensure that a post dated check you may present to someone else will clear once it arrives at the bank it was drawn on, s not to write it unless you can over the full amount. And to ensure a check you deposit will not get returned, you must not deposit it until the date written on its face is current or has recently passed.