Hotkey issues in Legacy Only Worlds

Hi everyone,

So I've seemed to run into an issue: I wanted to go legacy PKing (in NXT) but when I press the default hotkeys (F1, F2, F3...) to switch between different tabs like inventory, prayer, etc. the RS3 default binds are operating on top of the legacy ones. This seems to only be occurring in Legacy-only worlds.

Even if I clear or reset the binds in my control settings it doesn't seem to stick either, all I want to do is have my F keys control the normal functions they usually do in legacy.

Here's an example

Also, when I do try to change the keybind, upon pressing which key to bind (even after unbinding it prior), the RS3 menus still pop up & replace the controls menu.

Any help? Thanks!