Goes back to previous tool when hotkey is not held down

Hello

I’m having an issue where I’m trying to switch from my other tools to my pencil via hotkeys.

If i were to hotkey brush it would go to brush, but if i hotkey pencil it will only stay as pencil as long as i hold down the hotkey command, then return to the previous tool i was using once released. I haven’t had issues with this before, so i’m thinking i may have clicked something to make it this way?