double pane insulated window??? cold at night.. might be making a natural curl.. worse ... regardless.. that is some great lush vigorous growth.. so it cant be getting too cold at night ... let me put it this way.. if there was anything wrong.. it wouldnt be growing that vigorously ... eh?? if it is sprouting roots in mid air... i will guess you could cut the above off.. root it.. give it to a friend [hence the name] .. and yours will rebud below the cut.. anyone want to confirm or destroy that guess??? ken

Looking at the leaves and the tree structure, it might be a soursop tree. The leaves have a specific smell if rubbed in between the fingers, some people make tea with the leaves.

Possibly Yucca elephantipes. If so only hardy in zones 9-11. You could get confirmation or other suggestions if you post this to Name That Plant

It's an agave flower spike....yet to flower.