Text wont change in play mode and there's no errors?

I have a script that works perfectly in run mode, with a textbox that changes with a numbervalue (pressure). When I change the value in run mode, the text changes. In play mode, it's different, and there's no errors in the game. The script is a child of the textbox.

while true do
 script.Parent.Text = Game.Workspace.Core.Pressure.Value
 wait(1)
end