Open Radar

 
Summary:
My app Deliveries will drop a pin on the map, zoom into that area, then show the callout for that pin. If a different item is selected, existing pins are removed, and the same sequence happens again in a different location. If the timing is just right, the re-used annotation view will still have a callout visible from the previous item. I *think* the important thing in triggering the bug is to remove the annotation while the callout is still animating in.

Steps to Reproduce:
1. Run the attached project.
2. Click the "Drop Pin" button.

Expected Results:
Only one callout should be visible. Clicking elsewhere on the map should dismiss it.

Actual Results:
Often there are two, and only one can be dismissed. Sometimes you may see one callout to the left of the pin and one on the right. Sometimes they are directly on top of each other.

Version:
OS X 10.10.1 (14B25) and Xcode 6.1.1 (6A2008a). The bug is also present in 10.10.2 (14C99d).

Notes:
The attachment includes a screenshot showing one result of this bug, along with the sample project.

I'm not sure how much code is shared, but a very similar bug exists in iOS 8 as well. My iOS bug report is rdar://19507725