+xDo you have a screenshot please? It's hard to visualise from your description. Possibly a georeferenced airfield chart or approach chart was being displayed.
Unfortunately I don't. The airport was Jersey and the airport "map" was detailed but looked similar in format to that for my home (grass) airfield.
What I think was happening was that SD was switching maps but keeping the zoom level the same so the usual 1:500,000 scale map was completely unreadable.
When I next go flying myself I will see if the behavior is still there.
Tony