I’ve updated drivers for both mouse and keyboard, toggled numlock, and reset to default hotkey settings. I have even tested the buttons outside of the game (they work).
I have no idea why they all of a sudden stopped working. Any advice is welcome at this point.
check your mouse software. if it its anything like my mouse it has different profile settings and maybe you have switched profiles accidentally which caused the side buttons to be mapped oddly.
i know it has happened to me before.
since you say its working everywhere else that seems to be a likely cause. if not though maybe try deleting your settings for HotS, ‘variables.txt’, in the ‘…/Documents/Heroes of the Storm/’ folder and see if it helps out.