Sector capitals not showing up as part of a sector

I was playing some Stellaris and I noticed that one of my sectors had nothing in it. Turns out that most of my sector capitals had been identified as not being in one. I don't know if this is just visual, or is actually affected their bonuses, but is there any way to fix this?

Note: This is not just in my outliner, the planet screen for them lets me create new sectors as if they were not in one.