The horse was refusing, that is being "naughty", maybe the OP has never ridden a horse that stops. If a horse stops with me and I set them up right, the fence height was appropriate, the horse is sound, I will immediately give them a good wack or two for stopping at a fence. You need to make it clear to the horse that stopping before a fence is the one big no no that you won't tolerate. Expecting a horse to try is not asking to much. I also think the lines were the result of a sweaty coat, not cuts or welts. If the lines became raised and inflamed then they were being abusive. By insisting your horse is not allowed to stop, you eliminate the debate, that way if the jump looks different, moves, becomes a gate or box, has flowers, the one thing your horse has learned not to argue about whether or not they should jump it. Perhaps the OP has only ridden point and shoot horses and doesn't understand that it takes schooling them to make horses that way.
Troubled TB ~"A thorn by any other name will prick just as deep." @-'--,---