Fixed bug where depth buffer is not cleared if last object rendered on previous render cycle disabled depth mask.

src/renderers/WebGLRenderer.js

@@ -3178,6 +3178,11 @@ THREE.WebGLRenderer = function ( parameters ) {
 
 		}
 
+		// Ensure depth buffer writing is enabled so it can be cleared on next render
+
+		this.setDepthTest( true );
+		setDepthWrite( true );
+
 		//_gl.finish();
 
 	};