Does the bank have to provide any type of notice to a business account holder of any ACH transaction that has gone into/or out of their account?

You mean besides sending them a monthly statement, no - a business is no different than a consumer.

unless by contract through your Treasury/Cash Management area you have been contractually obligated to do such, such as a paid service you provide to said customer, through a positive pay product or some type of intra-day statement or balance process.

If you have such a contractual requirement, it would be good to make sure it can be done electronically. Ideally, if the business customer is expecting one or more ACH (or wire transfer) credits, it will check its account activity during the day. Or the bank's system may include a utility future allowing the bank to send a message (with the customer's approval) when those types of payments hit the business's account. Preferably something non-specific, such as "This is a notice of recent activity in your account number ending in ****1234."