Hi again, David (sorry about the system mixup in that other thread).
Since you’re not using X Theme, please test if leaving all plugins active but changing your theme to a WordPress default theme like Twenty Fifteen, Twenty Sixteen, Twenty Seventeen, etc. resolves the issue.
If it does, we know it’s a theme conflict. If it doesn’t, it could be a plugin conflict instead.
You might also see if you can spot any console errors at your site. (If needed, you may reference our KB article Using Google Chrome Developer Tools.)
Also, please enable WP_DEBUG and WP_DEBUG_LOG (which will create a file on your server at /wp-content/debug.log if there are any WP_DEBUG messages) and share any debug messages you see while trying to replicate this issue and doing other things on your site relevant to this ticket (such as visiting your site’s home page, events page, Photo View, single-event pages, and anything else you can think to do).
Please let me know what you find out from all this. Thanks!