UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2697.0 Safari/537.36

Example URL:
http://codepen.io/Krinkle/pen/NNaOpj?editors=0110

Steps to reproduce the problem:
1. Generate CSS gradient with hard stops.
2. Increase background-size to over 100%.
3. Set background-position to 100%.

What is the expected behavior?
Only one half is shown.

What went wrong?
One or two pixels from the other side of the gradient are rendered within the element's boundaries. Causing part of that half to peek through when it shouldn't.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes Chrome 49.0.2623.110

Does this work in other browsers? Yes 

Chrome version: 51.0.2697.0  Channel: canary
OS Version: OS X 10.10.5
Flash Version: Shockwave Flash 21.0 r0

Whilst it may seem arbitrary at first, the specific combination of an overflowing background gradient and background position are a common way to provide on/off toggle sliding effects in UI elements.
 

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	wikipedia-capture.png 345 KB View Download

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	codepen-capture.png 269 KB View Download