This is really common with mobile phones if you look at the cheaper chinese branded mobile phones and you check the incoming and outgoing traffic you will see that there is a load of traffic from advertisements which I consider malware as I did not agree to have them on my phone. I have had a couple of Chinese phones and some of them even had pop up adverts in chinese right from a factory phone. If you just Google about this it will bring up a load of different results. China is fucked up and they get away with it despite regulation from the USA. The USA have only banned certain big brands but its the smaller ones spreading like wild fire.
There's a saying going around: "if you've been given something for free, you're likely the product". Cheap phones aren't that cheap for nothing, I remember even Amazon had some very very cheap smartphone that was only cheap due to the ads it had everythere throughout its system. We're still so far away from creating privacy-focused mobile phones, and we're still
so far away from having people
care for real about their privacy.. Unfortunately, not even Bitcoin will make people care more. At least not enough people, because most are in just for the gains..