the only solution I could give is to make sure there are no spaces before the /target, otherwise it would be much like someone saying /wrists in chat with the added space so that they dont emote or get a message indicating that it is an invalid command. So just double check that, and if nothing... sorry I couldnt be of more help.

I do find it interesting though since I had read about another boxer who was having troubles with their casting being cut off without a /stopcast command. This was occuring regardless of the cast (not channeling), and would continue to the next spell. Leads me to believe that there may be a problem server side with some people's macros, but I personally havent encountered it. Anyhow, good luck