Help with a castsequence issue

#showtooltip
/castsequence reset=target/combat Ravage, Faerie Fire (Feral), Claw, Claw, Claw, Ferocious Bite

When i have the above on a hotbar and bound to MB3, when I have MB1 or 2 held down, it will not execute the casts (I use left(mb1)/right(mb2) mouse button held down to move forward/look while moving). When I do not have either mb1/mb2 held down it will execute the cast sequence Is this a macro issue, or a mouse issue do you think?

Replace the macro with a base spell, will answer your question immediately.