Last Episode Question

Does anyone have an idea of why the last episode had the long storyline of the Chief's baby? It didn't seem to have any relation to the plot and seemed like just a filler, as if the writers could not think of anything that related to the plot. Perhaps it was meant to show the humanity of the Chief in contrast to Bosch's seeming hatred of him at the end. But what purpose would that serve since the series ended and he will seemingly not be a part of he sequel?
Any comments?