That's because you check if the layer is visible at every tick, so when you press Start the actions that make the menu visible run first, but are then immediately followed by the actions that make that same menu invisible.
To fix this, write as main condition:
On gamepad 0 Start / Menu pressed OR On Escape pressed
then, insert two different sub events:
- if Layer "PauseMenu" is visible
-> display pause menu
- Else
-> hide pause menu
Like so? If it is; the result is still the same.