I am using Joomla 3.1.5 with the JSN Metro Pro template and the latest version of K2. I am trying to use my K2 tools module on the archive setting. It shows on the front page fine, but when I click on a month to view the archive results, the resulting container seems to have issues. When the page background is set to a light color (white and green), the container appears with a white background as I want. But when the page background is a darker color (blue, red, or violet), the container has the same color background as the page making the results very difficult to read.

Is this a problem with my K2 settings or is it a JSN Metro issue?

Since it has to do with the correct coloring of the block it has to do with your template settings. You can contact your template provider in order to help you with this issue.