I noticed that my hot converstation box is showing thumbnails for 2 articles that don't have thumbnails or images. It seems to have gone to my uploads directory and just grabbed 2 random images that absolutely nothing to do with the article.
How do I get it to stop doing that?

The thumbnails have zero relevance and it looks confusing.
As I can't control which articles are in the hot conversation, and in the long run less than 1/2 my articles will have thumbnails, this could become quite the issue.

is there a fix?

anointed-

I realize this is not a direct solution, but you might consider turning off "hot conversation" (One Theme -> Appearance -> Misc) and letting the recent comments widget do the job. Just a thought...

I didn't think it was possible for hot conversation to grab thumbnails that don't exist, especially if the article doesn't even have an image??

I would double check to see if those articles actually have thumbnails