When clicking on buttons you no longer have an animation that plays. Normally the button would get smaller as if you are pressing it down, that is no longer happening. This means there is no indicator you are currently clicking on that button.

When pressing down on a button, it should indicate that with a small animation which for example could make the button smaller. This would help to let you know you've clicked on the button and that as soon as you let go of it, it will perform it's action. (This is also what happens on Live)

The first video shows it's behavior in live and the second on in the current open beta. You will notice that in live the button SFX played on button down and not on button up, this was thankfully changed to match with when the action happens. Though the indicator for when you are pressing down is missing completely: