I am wondering if it could be because you have some structure or link left on the planet.
Things that would not have been deleted when you removed the command center.
Did you try open those planets in my tool and see if it reported anything built on them?
Or are they just empty ?
It is also possible that the API keep track of all the planets we colonize no matter their status at the present time.
Like you can add planets, but never really remove them.
And the game would filter the ‘empty’ ones automatically.
Out of curiosity, could you go to this API EVE Swagger Interface (evetech.net) - list of all planetary colonies owned by a character, and get the list of planets for your character that used those planets.
From the result, IF you see one of those you KNOW to be empty, pick it, then try it with the following API EVE Swagger Interface (evetech.net) - full details on the layout of a single planetary colony
And check if there are any structures/routes on it or if it is empty.
You can get your Character ID from the URL when you find yourself in Eve Who - Home
As for the planet ID, you can use EVE Swagger Interface (evetech.net) - information on a planet to check the name of a planet from its ID (because the PI API only use planets ID, so you’ll need to lookup the name to know which is which to find the ‘empty’ ones.
If it really goes along the line that the game automatically filters out ‘empty’ planets, then I should duplicate this behavior in my tool.
Which is why I am interested in the results of the API calls.