It has to be a bug - the land is water.
The land is blue. That doesn't make it water any more than the sky is water 
The usable tiles appear to be categorized correctly in that screenshot. The texture overlay is due to the special and shouldn't be related to the color of the planet or its terrain. So unless the planet is visually mismatched in the map vs the planet screen (which isn't clear from the OP since there's no screenshot of the map), it all seems to be working correctly other than the odd color combo.