Well, need more information in order to really help you. If you are just using /stick to stick to the mob, it shouldn't strafe around the mob. if you are trying to use /stick behind, im guessing you want to try /stick behindonce. Also, are you using mq2melee with either turning on attack or /killthis to engage the mobs? If so there are a bunch of settings that could be the issue.
And is your toon trying to strafe to stay behind the mob while that toon has aggro?