Jumping is not required for using abilities while running. Strafing is just as viable as jumping, without the position check de-sync that prevents you from being hit. I've watched streams of people playing BRD, SCH/WHM, BLM/SMN where they talk about how over the top this problem is. They purposefully take advantage of this to become practically invulnerable. Grouping with only ranged and caster jobs to exploit it to it's fullest. If none of your team members can die, you cant lose!

On a side note, don't come in here to drop the "QQ melee" bombs on us, when it's known that it affects casters and even healers casting animations as well.