It might be useful to have a look into the discussion on the same topic on the Microsoft forum at:
https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware/device-census/62ef3c01-56fe-41ec-a4bc-72f295e27b98
page 4 bottom, contribution by Varelse.
It seems that Microsoft schedules from time to time a search into the use of the camera, independent from any setting of the apps that can use it. These actions of the program DeviceCensus (in Windows32) are monitored by the Eset Internet Security and pop up every time. So any rule regarding Skype or whatever other application will not prevent the popping up.
