Overlays with MkMapView do not scroll smoothly

By overriding the drawrect of my MkAnnotationViews, I am displaying paths using CoreGraphics. T开发者_运维问答he problem I have is when I zoom in pretty close and scroll the map view, the paths drawn by CoreGraphics seem to be really jumpy, as if they are updated only after a shift of three or more pixels. When zoomed out, the scrolling is perfectly smooth and is reflected for each pixel shift. The drawrect function is not called during this scrolling as I assume mkmapkit is just applying translations on the existing views. Any ideas how to smooth this out or why this is happening?

Here is a youtube video that I posted showing the issue using the iphone simulator. Of course, I have the same problem on the actual device as well.

http://www.youtube.com/watch?v=AvWx5Yz4oxI