[5.4 - Unity2D - Android] UI Button Requires Child Text?

I made 2 buttons. I removed the Image component from both. Then I removed the text child object on Button1. Button2 has a text child object. I have the same On Click method on the buttons. Then I click on Button1 and nothing happens. Then I click on button Number2 and the method executes.

I then added a text child object to Button1 and after that the method executes.

I believe that the buttons are identical appart from the text child gameobject. So is it normal that this happens or have I just missed something?