Best answer by Mohammed
Nothing to be alarmed about here.
The iD App will reserve 50MBs of data when you open it when connected to mobile data.
This is just how the app operates.
If you try closing the app, turning off Mobile Data then turn on WiFi.
Opening the app on WiFi should show the 50MBs returned to you as normal.
It's only shown like this if you open the app via Mobile Data.