Answer
This is typically a missing media-library access permission, not something tied to that specific Entity Action on every screen — grant the permission set that controls adding and viewing items in the Media library (the same one used, for example, to let users add/view items on Incident Reporting's media pages). The same underlying media-library permission covers attachment/media functionality on NCR and CAPA as well, even though the specific Entity Action mentioned in other community threads for different screens doesn't exist for these particular windows.