NAM to GFS Switch

[java568]

I am not sure if this is a bug or a model issue, but I am leaning towards bug. When I choose a big city, it seems that the switch from the NAM to the GFS occurs at a different time than if I choose a rural area around the big city city.

For example, here is Little Rock:

Here is less than a hundred miles west of Little Rock (same time zone):

Is there a reason one switches at 6PM and one switches at 9PM?

Could this be related to this issue?
https://community.windy.com/topic/4534/nam-model-errors