Google collects Android users’ locations through cell tower data even when location services are disabled and our DTEK does not tell us.
https://qz.com/1131515/google-collec...-are-disabled/
This is the another point that shows you can't trust DTEK as
1: they don't monitor BlackBerry and google preloaded apps
2: they perhaps even can't monitor such now revealed hidden background functions in the OS