We have an application plugin which generates custom Annotations. When using a version of Acrobat 11.0.04 to current (11.0.07) our plugin, when run on a Mac with a Retina Display, draws the annotations in the wrong place and with the wrong size. When using 11.0.0 to 11.0.03 this is not an issue. I have an example that demonstrates this bug. I basically modified the Stamper example provided with the AcrobatXi SDK.
You can find the example here:
If you run with the plugin and try to stamp you will get white boxes. So you need to have a non-white background to see the actual boxes.