14/06/2019 4.22.2 You may experience the Launcher>Library>Engine Versions Update process loops continually, failing to update/resume/etc.
To fix this click Installed Plugins and Remove Substance Designer.
Then do the update.
Then reinstall Substance Plugin.
I also have ran into this issue, although I had to use a different method to resolve this problem.
I had to go directly to the directory of the Substance plugin and remove it directly. Then restart the Epic Games Launcher and perform the update/repair on UE4.
Substance Plugin Location: Unreal Engine\4.XX\Engine\Plugins\Marketplace\Substance
(“4.XX” - obviously your version will be here respectively).