I noticed a change of tones in one of my photos after upgrading to LR 3.4.
This is how it used to look (and as it was uploaded to Flickr):
And this is how it looks now in LR3.4:
Image is not available
Note especially the small patch of road on the lower right corner: it has distinctly green color cast in the current version. There are other changes in tone elsewhere in the photo, but they are much more subtle than the road.
And as you can see from the history panel, the image has *not* been modified by me at all in Lightroom since it was uploaded to Flickr (which is the version above). So it seems that some sort of bug has caused this color shift. Which is not nice.
Fortunately this is (at least so far) the only image which seems to be affected.
Using latest version of Mac OSX here, LR running in 64bit mode.