Just to answer your question, no it's not a glitch. It was designed that way. The primary reason was in the case where an IFR pilot used the CRAFT Sketch, departed into the clouds, and wanted a quick look at the CRAFT Sketch again to verify the information, then get right back to the map page, or whatever nav screen they already had up. If you notice, there are two Exit buttons, one of which is right where you clicked to get to the Sketch mode. That's so you can quickly switch back and forth without moving your finger. Once you Sketch something new on that page, this button changes to (I think) Undo.