Child objects behaving not as they should in preview

I can’t figure out why this is happening. I am following a tutorial on youtube and I have to make 2 objects children of a parent object. In the editor, when I move the parent the child objects behave as expected. However, when I press ‘P’ to see how it behaves, the child objects don’t move the same as the parent. Is this a known issue?


btw I’m using Blender 2.63