Google announced changes in the AMP Cache
Google announced the forthcoming change of URL schemes in AMP Cache. Soon, the cache will be one site with your own subdomain: https://cdn.ampproject.org.
This change will provide additional protection for the content that is displayed from the cache.
There were no immediate steps on the part of publishers have implemented AMP is required.
However, to benefit from the innovation, it is recommended to update the implementation of the CORS (technology resource sharing between different sources) to prepare for the new scheme URL in the AMP Cache.
Cash will continue to support the existing URL, but in the end they will be redirected to the new URL scheme.