I'm trying to be a Lightroom fan. I've enjoyed using it a lot since about 4.0. But this....?
"Our engineering team is working toward a fix for this issue. Until then, please use this workaround:
This occurs when Auto Tone has been applied to your images.
For existing photos, select all your images in Grid view, and then click the Reset All button in the Quick Develop panel. Then click the Auto Tone button to properly apply this feature.
To prevent this from occurring in the future, choose Lightroom > Preferences > Presets (Mac OS) or Edit > Preferences > Presets (Windows). Uncheck Apply auto tone adjustments."