Update:
I’ve narrowed the issue down to the two new files introduced in 1.2.0:
responsive-lightbox-lightcase > assets > lightcase.min.css
and
responsive-lightbox-lightcase > assets > lightcase.min.js
Everything works as expected on mobile screens if I replace references to those files in responsive-lightbox-lightcase > includes > class-frontend.php
with
wp_register_style(‘responsive-lightbox-lightcase-css’, plugins_url( ‘assets/css/lightcase.css’, dirname( __FILE__ ) ));
and
wp_register_script(‘responsive-lightbox-lightcase-js’, plugins_url( ‘assets/js/lightcase.js’, dirname( __FILE__ ) ), array( ‘jquery’ ), ”, ( Responsive_Lightbox()->options[‘settings’][‘loading_place’] === ‘header’ ? false : true )