Roll below jacket collar
I know we've talked about fixing it, but this question is about when it should and should not occur. My favorite suit jacket has no roll when I put it on and am standing normally. However, as soon as I tilt my head back or shrug my shoulders even the slightest amount I develop a small roll. So, is this worth seeking tailoring intervention or would just just leave well enough alone?
That sounds normal to me.
When you're moving, the jacket's not going to look the same way that it does when you're standing still. Tilting your head back changes the position of the collar, so it's not surprising that there will be a ruffle or roll. Your situations seems normal, but I can't tell without pictures.