I'm with you, but is it possible this helps in some way with nozzle movement that might not be easily visible? Just trying to figure out why it would even consider this placement.
If I reduce the count one it will arrange them in a neat grid, albeit with one row shorter than the other. And there is an element of randomness, if you click the arrange button again it will sometimes place the outlier on the other side.
I have no idea what the fuck its thought process is.
There may be multiple solutions to the fitness algorithm it's applying. So you may sometimes see one and sometimes the other depending on some "random" variable.
You have the right idea! The slicer takes all printhead movements into account and likely shaves off a fraction of the total print time by positioning one object like this.