I think white holes actually pop up from calculations outside of LQG as well. Specifically I seem to recall there's something using Einstein-Cartan as a basis,

I think white holes actually pop up from calculations outside of LQG as well. Specifically I seem to recall there's something using Einstein-Cartan as a basis, written by someone of note which predicts white holes as a permanent endpoint of evaporation. Then again, maybe it was rovelli? Alas, I can't seem to find the paper now. Google sucks and keeps dumbing down my query.