Hi,
we have a problem in our amp live football soccer page related to google amp cache.
We have the live of italian serie A and serie B football games The user can follow the live without refresh the page: in non amp page we handle it with javascript while in the amp one we use the tag amp-live-list with refresh time of 20 seconds.
If the user call the amp page directly there is no problem and the refresh is working well:
Example.

https://sport.virgilio.it/dirette/live/serie-a/26-2-2018/cagliari-napoli/3835/amp/

While if the user goes to the page from google search results and then from google cache it seems that the page is not refreshing.

https://www.google.it/amp/s/sport.virgilio.it/dirette/live/serie-a/26-2-2018/cagliari-napoli/3835/amp/

Our server replies always with max-age:0 and then google should not cache the page. Google should always ask the page to our server.
During the live the amp version of page is always lagging behind not amp page.
Can some explain me where is the problem?
Thanks