I’ve been using the commerce_currency_resolver module and it has been fantastic to use. One issue I ran into was with how the cookies are handled on Pantheon.
When using custom cookies a special naming convention must be used. The cookie’s name must start with STYXKEY.
Per Pantheon:
Respond to a request with cached content depending on the presence and value of a particular cookie. It’s important to note that in order for the response to be cached by Pantheon’s edge, the cookie name must match STYXKEY[a-zA-Z0-9_-]+.
Pantheon Documentation: https://pantheon.io/docs/cookies/
