After uploading an image there's a "Edit title / description" link in the top right.

Imgur uses Aviary for the advanced editing. If it doesn't have a blur option then there's nothing I can do :( However, there's a rectangle option, so you could just black it out instead.

I just tested the site using the exact same version of Chrome, and I did not experience this issue.

Could you please try it on a different computer? I have no doubt that you're having trouble with it, I just can't reproduce it.

After you upload an image there is a "Edit title or description" link in the top right.