It very well may be a bug in the MAC side of the code. I know it works in Windows and Linux.
However if you want the DEVs to take a look, this should be reported to bugtracker
. You will need to setup an account there as it is on a different system.
It would also help if you can post the ticket number here so other can see the progress, add information, or see the final results.
Be sure to provide the guests log file (as an attachment) and any other information that might help them to sort this out.