I'm currently working on a Magento 18.104.22.168 to 2.0.7 Migration and am almost at the final step where I can do the Delta migration but I've run into a problem with the currencies that are being submitted to Briaintree.
I've done a multi-store set up where each store will be for a separate country (USA & Mex) and have set up the settings for each website to point to a different Merchant Account ID within Braintree that is associated with its corresponding currency (USD for the US account ID & MXN for the Mexican account ID).
The problem I'm having is that when I submit a payment for the MX store it is being transmitted as the USD value instead of the MXN value. (e.g., USD$35.99 instead of MXN$691) and Braintree is understanding this as MXN$35.99 which would convert to ~USD$1.90. The currencies display correctly in the front-end and in the checkout process but they are just not transmitting correctly.
I've tried messing with the Merchant Country for each store/site and the Catalog Price Scope but no luck so far. Here are some images for reference: