I inspected a house yesterday where both bathroom fans terminated into the attic plus there was a leak into the attic from the chimney. I guess the home owner realized there was an issue because he added a dryer termination cap to the end (I’m assuming to keep the cold out in winter) and lay down plastic to keep the insulation from getting soaked. You gotta give him points for creativity. :roll:
I don’t know if I can track the pictures down but more than a few times I have found them feeding into an upright paint bucket right under the turbine.
Best design now is out into the soffit with a proper vent hood, no messing with cutting holes in the roof.