I have just found what might be a bug - or there is something I don't understand.

My fleet bases are full with 2 station flights and 2 Spacia raids, but I can still spy and send recyclers from the galaxy map. If I click through to the fleet commands interface, it shows that I have 4 fleet bases, but 5 fleet movements. I cannot go more than 5 though.

Is this an error related to the potential to have invisible attacks against aliens not counted in the fleet bases?

EDIT:
This only happens on my planet with 4 fleet bases, it does not happen on my 1 or 2 fleet base planets.