To begin, here's some information about the system I'm experiencing this issue on:
OS: Windows 10 Home version 20H2, x64
Java Version: 17.0.1
Mod Version: 1.5.0

No matter what I set it to or how I use it, the keybind to Toggle NBT doesn't function properly. To specify, I'm not having a problem with turning the advanced NBT tooltip on. I just can't disable it aside from using Minecraft's native method for toggling NBT tooltips. Every other keybind works properly, aside from Toggle NBT.

I have determined that I am, in fact, stupid.
I never considered the option as I hadn't ever installed Mod Menu on my instance. My issue was that the toggling method was set to "F3H" in the config. After changing this, it works properly.