It looks like it is on the U.S. Sectionals, but not depicted by iFly. I looked on http://vfrmap.com/?type=vfrc&lat=48.941&lon=-95.348&zoom=10 and it shows this:
I'm not familiar with this area, but my Windows10 desktop shows that the Northern part of this area is indeed missing at all zoom levels. There's an outline that disappears if zoomed in closer than 22:
Here's the history: https://www.minnpost.com/mnopedia/2014/02/story-behind-minnesotas-weirdly-shaped-northern-border/