I run an ACH keyword search for UI Benefits and had a customer hit where the customer is receiving UI Benefits from two states one day after the other. It's been going on for about two months. Is this something I should be reporting on? It appears he's given himself a 500% raise since the pandemic pay.

Yes - There have been quite a few advisories published on people being used as money mules and receiving multiple fraudulent UI payments.

Have someone call the customer, noting the multiple payments, and then asking if a change of address should be filed. That should at least give you an opening to ask the customer about the circumstances. It might clear this up, or it might give you some more info for a SAR filing (and whether to maintain the relationship).