This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
8 bit textures are darker than 16 bit textures inside of editor.
Expected : Same amount of saturation for both images
Result : 16 bit image is noticeably lighter
Head over to the existing Questions & Answers thread and let us know what's up.