Stop Channeling Penance

Hello guys,

I like to use stopcasting macro and in general it works great for every class but when it come to priest i have a probleme with 1 spell penance , cause no matter if i put the /stopcasting in any macro penance wont stop like it suppose to do for any other channeling cast like drain life or mind flay i would like to know if there is a way to stop the penance with a macro or is it a security from the game that prevent u to stop ur penance , ive been trying a bunch of things but it doesnt work thx in advance

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