Raids always the same set of bugs

[MR S P RUSSELL]

As the title says, every single time i'm raided the bugs that attack are the same. It always consists of, 1 ORC blue butterfly, 1 ORC ladybug and 4 ORC red soldier ants. I've tried this in various locations all over the park, still the same spawn set. I've completed all the story bar the MixR  as i'd like the raids to continue, just a little variety might be nice.