Attack speed differ when skill put on different position on bar?

not sure if this happenes to other skill, but i just start a new ult using cinder strike with bow. i put cinder strike on both right click and E. thats when i knotice the attack speed are different when i use these two buttons to activate cinder strike.
on E its like 12…3,
on right click its like 1…2…3

why is this?

ive upload two videos in my youtube account.
take a look. shot with phone

That sounds like a weird bug.

I think a short video with player logs would be worth posting in Bug Reports

Have you tried to relog the character in between the changes? Is there any visual change or just the tooltip?

ive tested a lil bit more, here is what i find out.
if cinder strike is only on bar once, no matter where it is, speed is fine.
and if cinder strike is on skill bar more than one position, only one key will have normal speed, and other two slowed