Microphone Push To Talk Mouse Binding Not Working in Menu

I use push to talk to communicate with my party. I've mapped my push to talk buttons to the default CAPS LOCK and added a mouse button (MOUSE 5). When in a game, I can use both buttons to talk and I see my username with the speaker icon on the right side of the screen.

When in the menu, I can only use the button binded on my keyboard (CAPS LOCK). I tried binding another key (É) and it also works (I can see my username with the speaker icon on the right side of the screen and my party members can hear me).

The button binded to my mouse (MOUSE 5) doesn't work in the menu. I don't see my username with the speaker icon on the right side of the screen and my party members can't hear me speak when I press the associated button.