I have encountered a bug in the quest system (God Mail), i a nugget required for the "bring my child home" quest dies the quest menu, accept and decline buttons become unresponsive.
I have not done any testing, and my findings are based on only on experience:
I accepted the quest, and went looking for the nugget child, i found him 3 min. later, and picked him up with telekinesis.
I proceeded to fly home with him, and drop him of very carefully, and as low as i could go.
He then smashed head first trough the terrain, and stated colliding with the ground again and again. Eventually he went through the mesh, and disappeared into the planet where he suffocated.
Then i went to check the quest, and the decline and accept button didn't work.
p.s the quest timer was also frozen.