Animals who do the "panic running" would path find to a block near the location where they were hit. When hitting them with a custom knockback enchantment item to make them go more blocks away, they walk in a straight line towards the block they originally targeted. This results in the mobs walking back towards the location they where hit at. They also don't attempt to jump over blocks when they need to.

Sometimes this doesn't happen but most of the time it does when hitting the mob (happen more than doesn't) I tested only on 1.16.5 with cows chickens and sheep, all same results. Also usually when colliding in a side of a block it seems to not happen. The knockback item was a renamed stick with knockback 8.

The video was filmed with a fabric loader but tested in vanilla 1.16.5 and still occurs.

It would be nice to fix because I use a custom knockback enchantment stick to move animals away when building but they come right back.