Thanks for those details @yayoi-d. The next time you encounter this, I'd like you to create a test project that starts from your real code base, and begin shrinking it down, since you're saying that a brand new Xcode project doesn't reproduce. The link above has good advice to use here, and going through a fairly course effort to shrink the project may reveal something specific to your project that is of interest. And if you get the code size down to effectively "just" a MKMapView with not much else when starting from your real app, and can still reproduce it then, I would file a bug report that includes the shrunken project, a sysdiagnose, and also a video capturing what you're seeing. If you file a bug report, please post the FB number here.
— Ed Ford, DTS Engineer