Hi Mike,
This hasn't happened in any version of WebViewer, so to clarify, you're requesting a feature? Since ReaderControl reads some configuration parameters from the hash we've disabled jQuery mobile's default hash changing behavior as it interferes, but even then this wouldn't quite give what you are looking for.
If you would like this behavior you would probably have to modify MobileReaderControl.js to update the hash when editing an annotation. The editAnnotationNote function would be a good place to start experimenting.
Matt Parizeau
Software Developer
PDFTron Systems Inc.