amp-auto-ads: ‘more than one .js’ warning

I have hit a brick wall here. If I install amp-auto-ads code as per the instructions, I get the ‘more than one .js’ warning.

Looking at the code, it seems to be installing two scripts: <script custom-element=…> and <script async custom-element=…>.

Why is the “non-async” part being added – the code from Google AdSense only states <script async…>.

Any help appreciated! I have currently disabled ads due to the errors but would like to resstore it right away. https://www.motoringresearch.com/car-news/most-economical-cars-2018/amp/

FYI, I am using the core plugin plus BOTH ‘Ads for WP’ and ‘Advanced AMP Ads’.