To add a little more information... I now realize this problem of restarting only applies if I was on the "Navigate to Geocache" screen when I switch to a different app. If I am on any other page (search, a cache's "Description", a cache's "Recent Logs", etc), then when I switch to a different app and return to the Geocaching app, the Geocaching app returns to the location I was previously at. It's only if I'm at the "Navigate to Geocache" screen (the map, compass, etc) of a cache that when I leave the app and return does the app start over. The obvious workaround is to come out of the map page and return to the cache's main page before switching to a different app. I'm not sure if it matters, but I'm using the latest version of the Geocaching app on an iPhone 4S using iOS 5.1.1.