That version of Mac OSX came out after the current release of the XDK. We have not tested against the XDK against it, yet. It is likely due to some compatibilities with node-webkit used by the XDK, which is not due to be updated until later this year. Also, none of us are using that latest version of OSX on our regular machines due to an embargo on updating to that version by our IT department for some (unrelated to the XDK) compatibility issues.
I'll file a bug reporting the issue. If you are seeing a request to send in crash reports, please do send them in, engineering does review them.