Automatic size, maximum width behaviour doens't seem to work

I am trying to set a maximum width for the automatic Size property.

According to

the size of the parent GuiObject determines the maximum extents that an automatically-sized element can resize up to.

from

So i did that but as you can see, the child extends beyond the size of the parent

(parent is selected)

(gif of the issue)

(pics of properties, both frames)

parent

child

Does anyone have any idea how i can solve this issue, all help is really appreciated

The model, i removed the non relevant elements

Edit

i have reported this as a bug, and they have acknowledge it and are working towards a fix