This post helped me produce a bug fix for the issue, and I have opened a pull-request on the Epic Unreal Engine repo on Github. The pull request has been approved, but are not yet implemented in any release as of yet (currently 4.22). If you are a member of the UE4 repo, you can take a look at the pull request on:
https://github.com/EpicGames/UnrealEngine/pull/5825