CSS rgba transparency bug in Chrome?

This looks like a bug!

I can confirm this misbehaviour. Got it also by using background: rgba(255,255,255,0.1). More weird: the calculated style says background-color: rgba(255, 255, 255, 0.0980392)

It is hard to see on cheaper displays using TN technology, but still possible to screenshot and measure with e.g. Photoshop.

This question is similar to:
webkit bug: input's background gets gray without any reason on focus?

The weird behaviour is still present in Chrome 38 and Canary 40. The fix that worked for me was to add a transform: translateZ(0); to the div with the rgba background.

This can now be fixed with the new will-change property. Specifically, will-change: transform;