Counterfeit cable has been a problem. A few years ago, someone found counterfeit cable with copper plated steel conductors. The outer jacket was suspect as well.
Wiring made in China isn't always counterfeit. Commscope, last I knew, moved production of riser-rated cable to China while keeping production of plenum cable in the US.
The upshot was to purchase cable from trusted/authorized sources to minimize the chance of running into substandard product.
