Hello @zingseven,
The AMP templating is very different normal theme templating, and plugin you are using is built with themes in mind so that is why it is not getting the correct data. To tell you the exact reason I have to dive in the code of the author plugin you are using.
Regarding hiding Author box only on AMP pages, I have given you the code, paste it into the Custom CSS box in the AMP plugin https://take.ms/hoYiS
and it will hide Author box only on AMP pages
This is the CSS code
#sexy-author-bio {display:none;}
Thank you for using our plugin, please do let me know if that resolves your issue or not.
Mohammed Kaludi
(Lead Dev of AMPforWP plugin)