hot spot on new roof
Notice that deeper snow below and to the left of the bare area? It's deeper than it is anywhere else in the picture: why?
It's very unlikely that that area was much better insulated than the rest of the roof, and so has melted much less. Instead, it's almost certainly a wind-carved snow drift, especially when you notice that the deepest spot forms a ridge sloping away from the edge of the roof.
With that in mind, it's pretty clear that your bare spot is just an area where the wind during your latest snow storm either didn't deposit snow or actively removed it. Once the storm was done, the snow has been melting everywhere; this spot was the thinnest, and so has become bare before the rest of your roof.
Summary: nothing to worry about.