Comments Box has set height and no scroll.

Have a look here: http://nexus.universaltheosophy.com/uncategorized/2nd-test-post/

The comments box has a set height of 315px, and scrolling is turned off. This is causing two issues: 1. wasted space below the comments box before someone starts typing, and 2. if you type a long comment, the lack of scrolling and set height cuts off the “post comment” button.

Not sure why this is, but it occurs on our main site and this subdomain, both are using the same theme (though different versions of it), so perhaps our theme is causing the issue…?

Anyone have a solution?

https://wordpress.org/plugins/jetpack/