Strange.. try killing all other processes and see if you can find if one bad actor might be responsible for this.
I think it's weirder than that. I made a small test script with one hotkey. If I run it inside the Scite4AHK editor, it works. If I compile and run it, it won't work in Pale Moon. I'm thinking it might be due to the fact that Toshiba has a keyboard hardware configuration thing for setting function keys to require FN key or normal. Although it has nothing to do with the function keys. I can set any hotkey and it won't work in Pale Moon. So it must be some strange keyboard side effect.
If you haven't heard of anything like this then that makes me think it's a Toshiba/W8 thing rather than just a W8 thing. But if someone with Pale Moon wants to try it, this script sounds a tone when Winkey-t is pressed and any FF derived browser 4.x or newer is the active window:
GroupAdd,EditorGroup, ahk_class MozillaWindowClass ;Firefox 4+ Browser
#IfWinActive ahk_group EditorGroup
I tried it compiled 32 bit Ansi/Unicode 64 bit. Won't work with Pale Moon 24.2.2 but it does work with any other Firefox I tried. It's just peculiar.
Edit: apparently Winkey-t has a function for taskbar in Windows. But it doesn't matter. It can be set to Control-Winkey-PGDN or something. It still won't work.