That is a curious effect

but I also see it. I hope I can explain it to you:
Thats why the npc always rotate to the plr to hit him. So if you run away the other character is in front of the plr. What could do the other npc. He makes it like the moon and circle around the npc to get his place. He is jealous

Maybe this is the solution:
desc = Melee Follow and Attack (close)
;Triggers
:state=0,plrdistwithin=500:state=1
:state=1,anyfurther=70:rotatetoplr,movefore=2,animate=2
:state=1,plrdistfurther=500:animate=1,state=0
:state=1,plrdistwithin=70,rateoffire:rotatetoplr,setframe=8,state=2
:state=2,framebeyond=8 60,plrdistwithin=70:plraddhealth=-10,sound=audiobank\misc\melee.wav,state=3
:state=2:incframe=8,rotatetoplr
:state=2,frameatend=8:state=1
:state=3:incframe=8
:state=3,frameatend=8:state=1
I did not test it!! I have not much time
Corno_1