Gmail takes a unique approach to how they handle media queries. There are three approaches for gmail, one is mobile first, the other is simulated responsive, the third is not responsive (i.e. desktop first). Most vendors take the 'not responsive' approach for gmail android app. 

By default AD does simulated responsive for google assets (true responsive for all other email clients). Simulated responsive is not perfect, but it gives you a reasonable view on gmail app and a good view in gmail desktop. The mobile first forces columns to 'fold' into one for gmail (and behave properly for everyone else). You can override the 'simulated responsive' to the 'mobile first' on a per row basis in AD. 

Click the row hamburger in AD. The properties accordion, select :

This forces all columns in that row to fold into one for gmail (app or desktop).