Software updates using mobile data even though set to wifi only

Hi All.

I recently started experiencing the strangest issue regarding my mobile data being used up. By system services - software updates.

i have an iphone 13.

twice in the last week this happened.

in SA we pay a lot for mobile data and therefore I use it sparingly and only buy what I need.

twice this week I bought 1gb and almost all of us was consumed by these software updates…

my iphone is up to date in terms of the iOS.

setting in mobile data is set to not use mobile data. Wifi assist, icloud drive and icloud backup all switched off at the bottom of mobile data.

i can switch off every app except the system services. And when I go in there I can see software updates used 1gb of data but it is not telling what updated or how I can switch it off.

please help!

I don’t know what to do anymore.

screenshots below. I reset the stats on monday morning after an update consumed 800mb sunday evening (while I was at home and at wifi..!!!!). Today it used 200mb while I was using an app which can be see below.

is there anyway to stop this from happening?