Goes back to previous tool when hotkey is not held down


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?