Documents and Data shows a larger storage than app
I own an iPhone 8 and I'm trying to manage my storage. When I look into the storage breakup within the settings (settings>general>iphone storage) and click into an app, the Documents & Data category of that particular app shows an abnormally large amount of data. However, when I go into the storage settings within that particular app, it shows a data amount that's nowhere near what is shown in the iphone settings.
e.g. The storage of WhatsApp shows 3.38GB of Documents & Data while the storage within the WhatsApp app (WhatsApp>Settings>Storage and Data>Manage Storage) shows only 876MB. I have attached pictures for reference.
I have the same issue with Google Chrome. Documents & Data amounting to 2.17GB is shown despite my having deleted all history, cache & cookies and downloads.
iPhone 8, iOS 15