responsive theme

Hi, just discovered that the plugin stops the responsiveness of the Legenda theme: https://themeforest.net/item/legenda-responsive-multipurpose-wordpress-theme/5888906
E.g. when making the browser window narrower.

From their support page it seems that they do not support caching in general. However, when I disabled Minify caching my page (www.jensengrill.dk) started working again. Is this the optimal/safe way of adjusting the plugin or should I also begin messing around with User agent groups (https://www.ninthlink.com/2012/06/29/disable-w3-total-cache-for-mobile-user-agents/)?

Looking forward to your answer ??

https://www.ads-software.com/plugins/w3-total-cache/