Focus cast button and macros do nothing

Hi all,

I am a returning player enjoying Blackrock before WOTLK drops like a lot of others.
However, I have run into an extremely frustrating issue and it's making me feel crazy!

When I enable focus cast key in interface -> combat, this key does not work AT ALL.

No worries, so I've made shift modifier focus cast macros for abilities to try it out- this doesn't work AT ALL (yes with combat interface button disabled).

I can set my focus both with keybind and unit frame right click perfectly fine as well. I have disabled all add-ons and tried once more and it seems it's not a conflicting issue with add-ons.

Has anyone else run into this issue before and know how to fix? Happy to drop whatever details below is requested to try and help. I have tried all macros out there that are google-able, I genuinely think there is an issue in-game causing this, but I don't know where to go from here.

Thanks