I spent quite a bit of time documenting and explaining all of the issues with our PCV system.
Here's a thread that provides an overview of the PCV related issues:
http://www.cruzetalk.com/forum/34-g...4-pcv-valve-cover-intake-manifold-issues.html
Here's a thread that goes into more detail on how the PCV system in this car works:
http://www.cruzetalk.com/forum/34-g...011-2016-cruze-1-4l-pcv-system-explained.html
Lastly, I designed a kit for the intake manifold that costs half as much as a new intake manifold, which permanently fixes the issue that would otherwise require an intake manifold replacement, which would, as you noted, fail again.
http://www.cruzetalk.com/forum/34-g...urbo-intake-manifold-pcv-check-valve-fix.html
These are all rubber components that fail due to fatigue and exposure to petroleum products and heat. They become brittle and tear/break or crack. There is no way to fix the valve cover issue, but fortunately that's the cheaper component, which is a simple DIY replacement for under $60.