As you can see in the two pictures, the wireless tag does appear in the Android app of the phone which is paired to, but it does not appear in the Find Hub web page.

The problem is reported by several users. It may be a bug or, if the tracker is a “Find My Device” network accessory, it may not appear on the web version due to a deliberate restriction by Google prioritizing security, privacy, and a streamlined user experience. See this question asked to the Google support team.