From the beginning of February 2018, AMP (Accelerated Mobile Pages) and Canonical Pages either should be match or should have “close parity”.
If not found then those AMP pages will not be considered for search features that require AMP. Google has decided enforcement of content parity thought it was requirement for some time.
Google has taken this step because of the use of AMP pages for limited context on teaser pages which offer limited and low content.
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