Noticed this problem a few time now with the latest update 5.2 on OSX.
When I sync some frames in the film strip, some of the frames that have been synced show up with a green preview. Image attached to demonstrate this. The white balance gets reset to some bizarre figure. The original that the images were synching from was set to Auto WB. So no idea why the program decides to change it. Clearly a bug, this has happened quite a few times now.