User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-25119729-20150526170115/@comment-5569775-20150526205431

I haven't had this issue, but if I had to guess, I'd say you should use "Large Only" gear. If you do, then it might be an issue with specific types of cats. I only really use Healing, Stealing, Bomb & Support cats/forte and the only one that occasionally goes after smaller monsters is the Support. The rest focus on Large monsters even when they have "Small Only" gear.