android 10 – Apps use mobile data when mobile data is off

My Android 10 phone seems to be using mobile data even when mobile data is turned off:

Data usage screen

The setting called “switch to mobile data automatically” is off FYI. The data, in very small quantities, is used by different apps including Facebook, Skype, Gmail and Google assistant; when the Wi-Fi is disabled, connected-no-internet or out of range.

How can I make sure the mobile uses mobile data only when mobile data setting is on?