In this example, the non-aligned unit attacks and then moves into a hex with adjacent adversaries.
Given a similar situation, a player (or regime) would seize the hex, but no added hexes would move to their control.
For note, non-aligned units also seize ZOC hexes when they do not win and when they do not seize a hex from an opponent.
It appears to me, after watching other examples, this only occurs with non-aligned units. I could, however, be mistaken.
I also believe this contributes to the zone fungus we see so often.

As an aside, per the history view, you can see in slide #2, the defender appears to disappear during the attack.
For reference, Game Build v 1.04-beta9; Scenario Build v1.04-beta2; Last Game Build used 104-beta9; Scenario Version Number #42.
I am running a Win 10 Pro 64bit, Intel i7-1065G7, 16GB RAM. It is a Surface Pro 7, connected to 2560x1600 display monitor via USB-C. That's Intel Iris Plus integrated graphics.

