No, not normal. Always good to rule out the physical but it sounds like behavior. Behaviors can escalate and it really can have as much to do with the rider. I've watched horses go through XC runs flawlessly and put a different rider and have bucks, refusals, evasions. Look at both you and the pony. Talk to the trainer who is your eyes on the ground about getting you through this. We can all give advice but not being there and only going by what is written could well mean we are off base.