Mac XCode 7.2 debug info about scrollbars suddenly appearing

Just updated to xcode 7.2 (and osx 10.11.2), and now I'm getting all these debug messages sent to stderr whenever my mouse crosses a scrollbar. Not loading debug libs. Qt libs are standard 5.5.0 release – I know this is likely something on the mac side, but I couldn't find anything on google – maybe it is some kind of interaction?

2015-12-11 00:25:48.766 emergent[24375:800640] outHitPart = -1
2015-12-11 00:25:48.766 emergent[24375:800640] inOptions:

{ "is.flipped" = 1; kCUIOrientationKey = kCUIOrientVertical; kCUIPartMaskKey = 768; kCUIThumbProportionKey = "0.3419354838709677"; state = normal; value = "0.196078431372549"; widget = scrollbar; }