If it is returning SSIDs it implies that at some time in the past someone created them, maybe these networks were created by cloning another network that had SSIDs.
I'd assume both API and Dashboard are correct, just showing a different view of the same underlying state.
SSIDs/other settings can exist even if there are no APs, that's desirable/correct behaviour, the API would be correct to return them.
Maybe Dashboard is reducing screen clutter by hiding the wireless details from you because there are no APs.
My guess is if you added an AP then Dashboard would show you the same SSIDs that the API is telling you are there - this is quick and easy to check if you have an unallocated AP, just add it to the network and see what happens, you don't need to plug in the AP, just add it logically, do the check, then remove it.