Scrolling code blocks glitch

Question

This is me trying to scroll left and right on this code block (animated):

Here are the still images:

This is a copy of the problematic code block, which I first found in this question

dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem

The problem appears to be the precise length of the code block (93 chars).

When I resize it to 92 or 94 chars, it is fine:

Screencast on YouTube

My System:

• Ubuntu 14.04.1 with Chrome 39.0.2171.65 (latest)
• Zoom levels of 75%, 90%, 100%, 110% (above that it creates a working scrollbar, below it removed the scrollbar entirely)
• Screen: 1024x1280, 17.1", 43.37cm