Hello again,
We did some testing and the following workaround seems to resolve the issue for some players:
In Windows go to Settings > Time & Language > Language > Administrative language settings > Change system locale > Disable “Use Unicode UTF-8 for worldwide language support”
If the box is not ticked, please tick it, press OK to save and then open it again and untick the box.
The only temporary workaround that definitely helps for now is to open the keybindings in WoW and set the same key you used before again as Key 2. This will allow you to use the same hotkeys as before and can be reverted once the issue is resolved.