It sounds like an issue with the way the sectors are being combined. Because I basically boolean everything together and booleans do not always give the best geo you can find strange issues like this. Try changing the sector group to see if that helps. Group A gets processed first and then group B so this is one way to get around these kinds of issues. You might need to adjust a neighboring sector instead of the one that is having issues but it is at least one more thing to play around with. I hope this helps and sorry to hear you are having issues.