Here is what I have tried so far, in addition to my earlier attempts -

I have confirmed that my INTERACTTARGET macro in Wow Key Bindings matches with the ingame key (I already use this key a fair amount, so i am confident it works).

I have given (as a test), the Paladin Protection Proc and Paladin Protection Sequence Macros a /click button name, and a key binding - I tested them both independently and together. In no cases did the macro execute beyond running to the NPC and /startattack.

I did not go through the exercise of giving every macro a /click name and/or key binding, as I figured testing with one class/spec would be sufficient.

I rechecked and confirmed that my character set was linked to all key maps, game helpers, action target groups, etc.

Thanks,
Ruab