I had to make some CSS changes to improve responsiveness on mobile devices and to accomodate the new layout options of Masonry, columns, and grid.
I tested these in the WordPress default themes and many popular free themes.
If your theme uses floats for things like widget areas or columns, you may need some additional tweaks to compensate.
If you previously added some custom CSS to improve the old [strong] shortcode template, even simple things like margin, I suggest you back those out and see how the new templates perform.
Of course, I will be glad to help. Just post a link to the site or contact me.
These structural changes should be the last. I believe we have solved some long-standing, intermittent issues. Thanks for your patience.
https://wordpress.org/plugins/strong-testimonials/