@Michelle2475 "I’ve talked to Airbnb about this in the past and all they can tell me is that it should work..."
The trouble with the (outsourced call center) Airbnb CS reps is you can't really put much stock in what they tell you. You can ask ten different reps the same question and get ten totally different answers. They often don't even know Airbnb policy. Rarely will you get one who actually knows what they are talking about.
It should be platform wide. I believe @Dean638 says it works for him as a UK host. It also doesn’t make sense it would be a feature for CAN hosts but not US. So my guess is it's a glitch for you. You can add to your house rules and your listing 'things to know' section that guests must go through the verification process to book with you, and when you get a request or inquiry, direct them to that and say once they've done that, you will accept their booking. Be sure to emphasize that it must be done within 24 hrs, if a booking request. Clunky, but the only thing I can think of until you can get someone at Airbnb to look into this properly for you.