Warning: Encountered two children Why does it render as duplicates?

Question

React

In one component, after loading, checkboxes appear, clicking on which sections with pagination are shown. Storage goes through

this.state = {
            products_data: []
        }

And then when we look at the following pages, we do a concatenation:

this.products_data = this.products_data.concat(this.props.products.item.data);

In general, section output and pagination work fine.
But then when you click on a specific section, information about it is loaded in the store, and another component is rendered, with a detailed view, and hides with categories. But at this moment the console is clogged with warnings:

Warning: Encountered two children with the same key, `506685`. Keys should be unique so that components maintain their identity across updates. Non-unique keys may cause children to be duplicated and/or omitted — the behavior is unsupported and could change in a future version.

I look, and when I open the detailed view, a component with categories is also rendered. And he starts duplicating them.
What is the problem?