Is the whole thing fenced that high and can you see all the way in? Maybe there's a pond somewhere you can't see? Or if you can't walk around the whole thing maybe there's a gap in the fence or it's a bit lower somewhere and they're just jumping in and out? :D
Hope the app sorts itself out and stops being a pain.
I haven't walked around the whole parameter yet... but there was a hole under one of the fences and the council was pretty quick to close that up so I'm kind of assuming they've been strict about the entire fence line.
I'll have to go for a walk around it. I'm so curious!