It really depends on the horse. Is the behavior on the ground vs in the saddle better or worse? I’ve learned that horses tend to test you if they don’t know your full potential as a rider. With some horses, you just have to assert yourself and show who’s boss. That’s why liberty training is essential. I really can’t explain why one horses reasons for misbehaving are different from another. All I can say with certainty is to try and read your horse individually and consider what the possible reason is for their behavior. Are they untrusting? Are they uncomfortable? Are there distractions?