Adding Child To Scrollbox issues

I recently came across that adding a child to a scroll box does not work for some reason and i have it in another widget inside of a widget switcher would that have problems

Adding child of a button UI

Player Controller

GameMode

Some Reason it does not add the child to the scroll box it prints it fine and the array is adding it fine

Clear Children
clearchildren

Error

The error says you try to act on a nullptr (ScrollBox_1) so the scrollbox variable is invalid.

ok