The funny thing is I just resign from MIUI beta team because of adware in cleaner app.
But I still have unwanted icon and news feed in default browser 060915 xiaomi.eu rom.
If you check official global rom zip file cust/in (india) you will see there is an extra zip called aplication_cache.zip...
Unlock it one more time, after that no need to unlock again when change to official rom or xiaomi.eu rom.
From what i know, this is the only choice if your flash twrp.
Ii will relock bootloader only if upgrade from v.5.1.
If you got stuck at mi logo or soft bootloop after install mm6 rom. Just re unlock again, will be fine after that.
It happened to me before.
Unlock your bootloader
Backup
Flash recovery/boot twrp.img
Mount system partition as read only
Completely clean-- Wipe all caches, internal storage, data and system. ( Dont wipe external sd card, cust , etc )
Install xiaomi.eu rom
Restart
Restore your backup.
Enjoy!
Then next update only wipe...