On button 1 it's unlikely to do Sunder at all, since the shouts are less rage. But it should do eventually on button 2.
It might be because you have made only one macro? As I mentioned in post#2 "I send multiple actions at once, most are macros defined in ISBoxer so that I can keep my toon's action bars clean for solo play."
You can open Game Helpers in ISBoxer
https://isboxer.com/wiki/World_of_Wa..._Macro_Library
Make a new folder "Warrior" then for each macro snippet make a separate macro and assign a keybind, so I have
shift-ctrl-alt-1 "Charge"
/cast [nostance:1] Battle Stance /castsequence reset=combat/15 Charge, Bloodrage
shift-ctrl-alt-2 "AoE threat"
/castsequence reset=combat Battle Shout, Demoralizing Shout, Thunder Clap
shift-ctrl-alt-3 "Revenge"
/cast [stance:1] Overpower; [stance:2] Revenge; [stance:3] Execute
shift-ctrl-alt-4 "Sunder"
/cast Sunder Armor
etc
And in my mapped key for button 1 "pull" I have 1 step with
4 actions,
https://isboxer.com/wiki/Named_World...t_Macro_Action
1. WoW macro 'Charge' in Warrior -> self
2. WoW macro 'AoE threat' in Warrior -> self
3. WoW macro 'Revenge' in Warrior -> self
4. WoW macro 'Sunder' in Warrior -> self