Something similar is happening with me. On place where thumbnails should be now there is half of the first image. On click it is not opening lightbox just open file in a new tab. Strange thing is if I enable css and JS minfying options on litespeed cache the problem is no longer appears and everything is back to normal.
This reply was modified 2 months, 4 weeks ago by Bobkata.
I had similar issues. I had to update my theme’s CSS to fix the sizing of the main image. I was getting two copies of the image. One outer and one inner, and there were two sets of expansion arrows. Click on the right set and the image was loaded in the browser (no lightbox), click on the left set and the lightbox loaded as expected.
I also had to put in updates to get the previous and next arrows to show properly. The previous version of the plugin had some CSS for those prev/next arrows which was changed/removed with this version. Instead, the button styles for my theme took over and I had to override those.