These two comments have the same score, but the scores have a different "hotness" color:
The upper comment I just upvoted. It displays correctly when I reload the page, though.
It looks like a CSS class isn't being applied here when the score is updated inline — this is the generated HTML of the score numbers in the above screenshot.
<span class="" title="number of 'great comment' votes received">2</span> <span class="cool" title="number of 'great comment' votes received">2</span>