In GA4 reports, the correct parameter to use for shared content is Content ID, not item_id. When running a report in Explore with item_id to look for information about shares, it will not yield the expected results. Instead, search for Content ID to find the value of the item_id parameter for the share event.

Using item_id in GA4 Explore reports does not show expected results because, for the sharing event, the item_id parameter is actually referred to as Content ID. If you have an ecommerce and run a report with item_id, you might get results that are not related to the sharing event but rather to ecommerce activities.

To correctly track shared content in GA4 ecommerce reports, you should use the Content ID parameter instead of item_id. This is because item_id is used in a different context within ecommerce, and searching for Content ID will provide the accurate tracking information for shared content.