Been there, done that ;) I had the same issue after someone suggested to me use Magisk - Magisk Managerr - Magisk Hide to succesfully hide root. I was on SuperSU rooted system and before installing Magisk I tries removing SuperSU with its app but ...
One question please
Clean installed the new update 1.2 but SuperSu is not installed ???
Mate, try installing magisk 10.2, it automatically install phh supersu and you can hide root from everything! Safety net passed, Android payement working, pok...
I tryed flashing exposed 87 with no luck. Any ideas9
Xposed is still under development for Android nougat and nobody can have a working xposed for the moment, it's normal it doesn't work.
Just wait until there is a release for Android 7...