Thank you for providing the logs. This appears to stem from a content issue with textures:
[ 0]LogWindows: Assertion failed: (TextureWidth > 0) && (TextureHeight > 0) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.3\Engine\Plugins\Experimental\Paper2D\Source\Paper2D\Private\PaperSprite.cpp] [Line: 586]
Our engineers are currently discussing the possible reasons for this.