Faulty casing ejection - Watchtower Firearms Durabolt 5.56 Bolt Carrier Group (BCG)

I bought this BCG to try it out. Put in a 10.5" 300 Blackout pistol after cleaning it and throwing on a coat of oil. Experienced sparatic case ejection malfunctions. Threw in another BCG and problem solved. Broke down the BCG and found a piece of plastic underneath the gas key, and the ejector spring wasn't releasing. Not what i expect out of a sub $100 BCG, ill stick with Aero, BCM, or another company i trust.