Hello, Flat Earthers!

I have a simple question that should be easy to answer: Why at sunset do I see the shadow line slowly crawl up a mountainside facing the sun? In the flat earth models I've seen, this doesn't make sense.

In flat earth model 1, the sun is a spotlight that focuses on certain areas of the flat earth. With this model, the shadow line should crawl DOWN the mountain on the facing side, as opposed to up.

In flat earth model 2, the sun is an omni-directional source of light, but fades into the distance. With this model, the sunlight on the mountain should fade away all at once.

Please assume in these examples that the mountain is sitting on an empty plain.

Explanation?

Thanks!