Ignore multipoints (as opposed to polylines and polygons) when adding annotations, just like we ignore multipolylines, multipolygons, and shape collections. In osxapp, break multipoint features into points before adding them as annotations.
Mapbox OS X SDK
A library based on Mapbox GL Native for embedding interactive map views with scalable, customizable vector maps into Cocoa applications on OS X 10.10.0 and above using Objective-C, Swift, or Interface Builder.
This SDK is analogous to the Mapbox iOS SDK, and much of the iOS SDK documentation applies here. Mapbox does not officially support the OS X SDK to the same extent as the iOS SDK; however, bug reports and pull requests are certainly welcome.