I'm having the same problem as this person: Fn Media keys slow/delayed on ubuntu gnome 17.04

I've already looked everywhere, and I could not find an answer. AskUbuntu, the Arch Wiki, Reddit, Discord, IRC, etc. Nothing. I don't think I can put much more detail into this because it's the same problem and it happens every time without fail. Not happening on Wayland, so indeed an Xorg issue.

This also happens on the Budgie desktop and on the default Gnome desktop, so I'm starting to think that this is something to do with Gnome/GTK but I have no idea how to fix it on my system, absolutely no clue.

I'm on Ubuntu 17.10, on Intel Integrated Graphics on an i3 3217U and 8GBs of RAM. Laptop model is an ASUS X550C.