When settings>device care>storage>clean now an android icon sometimes appears with Chinese characters beside it is viewed. This also happens while in safe mode. Google translate decode the characters as "super site monitoring/super field monitoring". Has anyone seen this?
In that screen, it is listing the apps that have files stored on your device. So this means that some 3rd party app that you installed has created temporary files.
Once this 3rd party app creates this file, booting in safe mode won't change the visiblity in Device care.