Rays, I heard GRN ships can move only to Taus no further than that. What were you doing there?
If you didnt know few things about Kusari and Bretonia let me write down this for you:
-Bretonia is working with outcasts in campaign against corsairs. The maltese knights have common with the bretonian knights, that is from where comes the friendly relations. Both of them knight's societies want "Corsairs to be removed from the face of the Sirius ". And since kusarians are hunting down any outcasts in their space just like bretonians are hunting corsairs in their sovereign, outcasts will clearly take bretonia side in any KNF vs BAF encounter just like corsairs are always going on Kusari side.
-Kusari is working with corsairs fighting together the bretonians and outcasts. Just because the outcasts are on bretonia side, in such encounters, the corsairs will fight for kusari side, to help them achieve the "Defeat of Bretonia" campaign and "repelling the outcasts from Kusari space" (in that name system leeds which is 50% to kusari (for now) ).
If you want to know more go to wikipedia and read more about the Outcast and Corsair factions.
It happened before and it will still happen that Outcasts will fight on Bretonia side against Kusari just like corsairs will fight on Kusari side against Bretonia.
Here little evidence: BAF ID
I am pointing at : "■Cannot ally with any unlawfuls except with the Golden Chrysanthemums or Outcasts"
Here little more: Outcast ID
I am pointing at: "■Cannot ally with any lawfuls except with Bretonian lawfuls against Corsairs, Gaians and Kusari lawfuls "
I hope this is enough information to solve your problem.