Yes, in post #8 the red line is visible to me. I seem to recall that it is possible to disconnect something from the layout box without actually removing the box. Which means that Misty's actions to move things around aren't totally definitive at eliminating this as a layout box.
If the original members of the layout group are disconnected but the layout grid is still present, you would get the result she showed in post #8, but if you look carefully at post #1 along the left edges of the labels, that thin red line is there too. I don't know how my old macular degenerated eyes can see that, but I can.
The line overlaps the label or text box that is above the aligned items in #1, that box where the text starts with "Use this form..." - and the line goes horizontally through the bottom quarter of the letters in the first text line of that box. The vertical line rises perfectly aligned with the left edge of the labels but is a very small distance inside the afore-referenced label or text box that is above the other items. If that was a screen capture then to me it is a quite real feature/anomaly.