Two issues:
1. I have a photoblog and all my photos are named like _MDDXXXX (_ - shot with AdobeRGB profile, M - month, DD - day, XXXX - index), I've installed 2.8beta1 and now it drops the "_" from the filename on upload.
Also, it doesn't attach the image to the post in the media library and my theme (AutoFocus) needs that behaviour. Now I need to manually attach the photo to the post.