vgamepad PS4 controller emulation issue

Question

Using vgamepad for PS4 controller emulation, the virtual gamepad isn't responding to button presses. Initialization, button constants, and regular updates are in place. No errors reported. Any common pitfalls or suggestions for troubleshooting?

import vgamepad as vg
gamepad = vg.VDS4Gamepad()
if joystick.get_button(0):
    gamepad.press_button(vg.DS4_BUTTONS.DS4_BUTTON_CROSS)
else:
    gamepad.release_button(vg.DS4_BUTTONS.DS4_BUTTON_CROSS)

Edit:

I noticed that gamepad.press_button(vg.XUSB_BUTTON.XUSB_GAMEPAD_RIGHT_THUMB) emulates the triangle button but not the others.