In previous versions, when you clicked on a stack of ships, the top ships would be selected.  Then, when you clicked on the stack again, the next ship in the stack would be selected.

Something has changed because, while the first time you click on a stack of ships still works as before, subsequent clicks do not.

The first screen snapshot shows what a stack of Onyx Hive ships looks like after I click on it.

The second screen snapshot shows what the stack looks like after I click on it again.  Note that, while the ship at the top of the stack visually has changed to a single ship, the tooltip that appears when you hover over the stack and the fleet description in the lower left-hand corner both still refer to the starting 4-ship fleet.

The third screen snapshot shows what the stack looks like after I click on it again.  The ship on top of the stack is the same single ship, but now the tootip and the fleet description have now changed to describe that ship.

In summary, it now appears to take 2 clicks to advance between ships in a stack instead of 1 and I do not see any benefit to requiring the extra click.  In fact, having the picture and the descriptions out of sync is not good.