This question already has an answer here:
The percentages are improperly aligned for me on the Privileges page, as seen below. It only happens with 3 or 4 of them because they are too long.
If the sidebar were about 15px wider and the mainbar 15px thinner, the issue would go away.
I'm using Chromium 25.0.1364.172 on Linux.
Related: https://meta.stackexchange.com/questions/67609/text-sometimes-overflows-margin-in-privileges-section?lq=1, though that question refers to a specific item that only overflows when you click on it.