OnClicked event of UMG button fires once in twice if virtual joystick is receiving input.

OnClicked event of UMG button fires once in twice if virtual joystick is receiving input. Both Andorid and iOS devices are affected.

This issue is found with 4.9 update. under 4.8 are fine.

1) Create new widget, add button, create onclicked event and link some functionality to see event firing.
2) Make widget to show up
3) Run in a mobile device, try to touch the button while controlling virtual joystick.

Expected: Event fires whenever button is clicked.
Result: The event fires once in twice.