Recently updated from 13.0.1 directly to 13.0.5 on OS X and using a non-Retina display.
The Info panel pixel value readout is wrecked in 13.0.5. Each image pixel seems to be sampled as a 2 x 2 array of sub-pixels (maybe something to do with Retina support), and that array is offset by a half-pixel upward and leftward. One can get four different pixel values from a single pixel now, depending on which quadrant of the pixel is sampled! See image below.
I remember reading a similar report in this forum about six months ago when an update was released which I opted not to install. I've been waiting nine or ten months for a 13.0.1-introduced bug to be fixed and have now abandoned hope. This bug seems to be going the same way: set in stone.
That a good possibility for that problem does not exists in the PC Windows not cloud version on CS6 13.0.1 x64.