I am looking at various implementations of the Isolation Forest in python and R. Both sklearn in python and solitude in R use a y variable with the ExtraTrees regressor.
Since, Isolation Forest is unsupervised, I am wondering why it is being turned into a supervised problem? Wouldnt this be an issue when scoring on previously unseen data sets?
For example sklearn (python) line 248 has this.
And in solitude line 144 as well.