Please come and upvote my bug report: [Launcher] Unable to install Low Entry plugins after installing 4.12.4 - AnswerHub - Unreal Engine Forums
I was told to contact Epic through their support section on the website, which I did. And now Epic told me that bug report belongs on the AnswerHub. So, unless you folks come and upvote it, it will be bounced around and then forgotten.
Thanks