Good news! Jilanico found the fix, go into your profile settings and make sure both english and undetermined are selected (I had to ctrl+click them, they were both highlighted blue when I clicked save settings)
No. Karma is a fake metric and can adversely effect others perception of a current comment. Comments should be judged on their own merit. One can have differing opinions or views that may be viewed as negative; however positively contribute to an active discussion with a agreed view.
Do you perhaps use Top Daily as your sorting? If there are no top posts today (no-one has voted), there's no posts that can be shown. I can see the posts just fine, but if I change to Top Daily, there's nothing. Newest post to that community was made three days ago.
I have the same problem in several communities including the one you linked. I also have the issue of only being able to see the first page of posts in some communities, but clicking on the Next button yields no posts on the next page when I know there are more posts.