since a month to this part active skill can be interrupted like vengeance , shield of faith and many other
its dont exist a concentration for attck speed skill based so tell me how can be interrupted ofc not by switch, trick , stun and all skill that remove target
ahh and btw sistem messagge dont say taht cast has beeninterrupted u just use skill and dont have effect
edited
Same as you can interrupt Frenzy, Zealot, Stun Shot etc .... Just target switch :) Check it .
aftrer some test :
if iron shield activate it during u pressing shield of faith or any other skill that skill will be interrupted