This is very common in the aftermarket, not so much in OE. But it can happen from OEM producers.
Example in my industry: Meritor, OEM for truck axles, makes (or, actually, purchases) brake shoes. Some are made using new parts. Others are remanufactured. When a customer buys new repair parts they return "cores" - the used parts. Then, the reman facility cleans up the parts; inspects them; may do some further manufacturing; and then re-sells the remanufactured parts.
In my industry this could be a steel brake shoe. Friction material is attached. The friction material wears out (by design.) When the product is replaced, the customer returns the old steel shoes. The reman facility strips off what's left of the brake lining; cleans; inspects; installs new lining; and resells.
Our company makes new brake shoes... our most frequent competitor is a remanufactured brake shoe. The "core" may be re-used 5 - 10 times. Often we sell new shoes to replace the cores that have rusted beyond recognition.
Meritor, the OEM, uses new product on their axles but sells reman parts in the service channel.
Many QA challenges in this industry. It's crazy.
best..............brad