This bug isn’t anything too bad, but it does affect visual layout.
I have a category named “Photography” (with a capital ‘P’) and a tag named “photography” (with a lowercase ‘p’). The TDO tag cloud spits everything out right, including the link, but it seems to be inheriting the casing of the word “Photography” from the category, rather than the tag itself. It’s actually affecting the backend in some way, too.
It’s very odd.
I know that it’s doing this, as when I went and to the backend “Post Tags” page, my previously lowercased “photography” tag started out with an uppercase “P.” I edited it to be lowercase, and then next thing I know my “Photography” category is suddenly lowercased, too; the two are no longer independent. Unless this is a WP bug itself that I’ve not encountered before, it seems that TDO is linking up tags and categories a little too much.