Page up keybind not working

Page up key is not moving play head back one frame. Page down moves play head forward one frame, and shift page up moves play head back 10 frames. Ive already checked my keyboard shortcuts and Page Up is set to move play head back one frame, it is just not working.I've tried deleting that action from the key saving it and readding it still not working. Ive also uninstalled and reinstalled after effects. Is this a Bug?