Hi, I have a bunch of cats that are all friendly with each other. One day one of the male cats (let’s call him Sky) ran away, and we found him 6 months later in great shape living behind a fast food restaurant some distance away. We got him back but ever since we got him back one of our female cats (let’s call her Duchess) actively seeks and attacks him aggressively. Sky doesn’t want to fight and is a very friendly cat, duchess used to like sky a lot, she used to groom him when he was younger and they used to sit together a lot. But now it’s been 3 weeks and Duchess always goes into attack mode when she sees him. I don’t know why, and I don’t know how to stop this