I am having the same issue. I switched back to the default theme and the issue is still there so it must be something within the core files. I am looking into the issue now.
So I’ve been having some troubles with a few buttons not showing up or working properly, one of them being the “Post Update” button on the Groups activity page. I figured out that the reason why some of these buttons were not showing up or working properly was from my AJAX.
Without reading too much about AJAX in WordPress, I added in header.php:
in order to get AJAX to work. This aparently was calling all of my AJAX scripts when they weren’t supposed to be called, therefore interfering with other AJAX calls.
After removing that from header.php, all of the buttons my site began working normally.
