PakBlacklist does not seem to be excluding files properly

The pak-blacklist files do not seem to be working fully. While some of the files may be excluded Engine/Content/Slate files are staying behind, which can be seen once you've used UnrealPak

1. Create a new project or download the large zip file here: [Link Removed]
2. Add ../../../Engine/Content/Slate/ to your PakBlacklist-Development.txt file
3. Place the PakBlacklist-Development.txt file in your Build/Platform folder
4. Package the game for Development
5. Open a command prompt inside of your D:\Epic Games\4.10\Engine\Binaries\Win64 and type: UnrealPak.exe C:\Users\samantha.sutton\Desktop\Yes\WindowsNoEditor\Yes\Content\Paks -extract D:\Extraction

Result: The Slate folder is still included once the pak file is extracted with UnrealPak
Expected: The Slate files should be blacklisted from the package