Xrandr and i3: Command for Dual Monitor needs to be run twice (why?)

[BonfireAtNight]

Maybe I can better explain the issue with a series of screenshots:

1. As can be seen in this screenshot, per default xrandr thinks my smaller screen is on the right (when in fact the physical monitor is on the left). This can also be seen in arandr.
   
   
2. Now, what I want is to take the part on the right and bring it over to the left. So, I reversed the order of the screens in arandr.
   
   
3. Now, after I hit Apply in arandr, this is what my computer thinks I should see:
   
   
   
   Everything would be nice. The right monitor would contain the two windows it held before; and the smaller monitor would be the screen on the left.
4. However, this is what I actually see:
   
   

So, maybe my question should instead be: Why might the virtual representation differ from what I actually see?