I encounter the same problem with Rig Manager Version V2.0.19. I do not have duplicates of the file "OS 5.1 Delay Update.rigpack" in the folders
"C:\Users\[yourusername]\AppData\Local\Kemper Amps\RigManager\Rig Packs" or
"C:\Program Files\Kemper Amps\Rig Manager\Rig Packs"
but i can see them in the "Locations" section of Rig Manager (Rig Packs Folder).
I found out that i can fix this issue by uninstalling the Rig Manager. After that you have to delete the Kemper Amps Folder from the "C:\Users\[yourusername]\AppData\Local" folder (make sure to backup your local library before that -> for me it worked to just copy the folder "C:\Users\[yourusername]\AppData\Local\Kemper Amps\RigManager\Local Library" before i deleted the Kemper Amps Folder and then copy it back after the reinstall of Rig Manager)
After reinstalling the Rig Manager it starts with V2.0.17 and everything is just fine. Then the program asks for the update to V2.0.19. If you accept the Update the issue reappears.
So just stay with V2.0.17. and everything should be fine. Hope this helps. I assume Kemper will fix this issue soon 
Cheerz