Errors when trying to use wix-bookings / wix-pay from Corvid

We are creating a custom bookings flow, its all working to fetch services and select a time slot but I’m getting an internal wix JS error when attempting to call wixBookings.checkoutBooking

I have no idea why wix-pay wouldn’t be set up on that object internally. I can use wix-pay by itself to create a payment just fine.

// The slot and formFields are valid, it fails when calling checkoutBooking
const checkoutResults = await wixBookings.checkoutBooking(bookingInfo, { type: 'wixPay_Online' } );

/* This is the error in the Developer Console:

wix-pay.dao.ts:9 Uncaught (in promise) TypeError: Cannot read property 'startPayment' of undefined    
at wix-pay.dao.ts:9    
at _r (checkout-booking.ts:27)    
at Object.<anonymous> (checkout-booking.ts:22)    
at tslib.es6.js:100    
at Object.next (tslib.es6.js:81)    
at a (tslib.es6.js:71)

Here's the code from that file that its failing on:

export function payWithWixPay(snapshotOrderId: string){
    return self['wix-pay'].startPayment(snapshotOrderId, { showThankYouPage: false }).catch((err) => reportError(wixPayErrorsMapping[500],err))}

I can see in the Network calls that a POST to /_api/frontend-module/booking succeeded:

And returned the following response: 
{  
    "errors":[],  
    "booking":    {      
        "wixPayPaymentId" : "ea1b80da-74ec-41fa-b8e5-96f6b3a51257",      
        "id":"4ed5ac3c-3fa1-41c0-83da-37d2d2b202b4",      
        "status":"PENDING_WIX_PAY_APPROVAL"    
    }
}