Sometimes I see the strange situation (and this just happened on my last turn): I successfully invaded the planet, and all my troops are on the surface

, but I cannot take it back, because right in the following turn my invading fleet is orbiting totally different planet! So I need to tell them "load", wasting one precious turn for it.
Why it's so? Is it normal? Can it be prevented, if it is?
(BTW, it's the turn right after my last autosave that was sent to Support to investigate Gargals hostility).