Ok, so I have the same issue as the user who owns a "THL T9 Pro". My issue is worse, I can't uninstall anything.
Thanks to Sophos Mobile Security it warns, stops and gives me the option to uninstall the "adware" or whatever comes up.
Yes, ran MalwareBytes for mobile phones, found out that PUP.Riskware.Autoins.fota.ins is on the system, belongs to the "system update".
The phone also have a 32Gb SD card installed, and also today found hiddenAds.Moo, and could remove it.
Thing is, that every time I go online, wifi or mobile, it starts to download something..
..But still tried to all the steps, can't do anything.