Hi there,
As the Cornerstone is built into Pro you might see the same incompatibility with the Members plugin you have mentioned. The only solution at the moment is that you use the X theme and turn off the Cornerstone whenever you want to moderate the comments.
Actually, if you use Pro you will not have a separate plugin for Cornerstone to deactivate while moderating the comments and that process will be impossible.
Unfortunately, you need to consider having another plugin for that purpose.
The CSS classes of the Pro and X are the same but when it comes to the latest version. I see that you use the X theme version 5.1.1 with the Cornerstone 2.1.7. Those 2 versions are not actually compatible. Please backup your website and update the theme to version 5.2.5
Thank you.