Looks like a bug, but I haven't seen it posted before. Weird
Do you have cinematic mode or options changed for icon displays? It could be that it gets confused with various settings and shows the icon twice - for example in cinematic mode it will still show the icons if you have ships selected, so it could be that it shows it once due to other settings, and once more if you're selecting in cinematic mode. But that's just a wild guess
