I just created a new Solution in Xamarin.Android (Studio 4.2.3 Android 4.12.2).
When Xamarin finished creating all the new files, it said there was an autosave file for MainActivity.cs. Out of curiosity, I loaded the autosave file and indeed, it looked like code I had from months ago on a completely different project. My guess is that I used a Solution/Project name that matched one I had used before.
Is this intended behavior or possibly a bug?