I was meet a very strange issue with Magento 2 number of products. There has a question here on Magento StackExchange: Wrong number of products in category. But my situation is different to him.
In my categories, there are no subcategories nor any products. But the number inside brackets is 1xxx. I tried to reindex (clear cache...) millions of millions times, but there is no luck, still same result.
Anyone here ever met this before me? Or better if you knew what was happened.