Cancelled bookings causing problems

When we cancel bookings we often see erratic behavior (dates aren't freed up in the availability calendar, and sometimes we get json errors in the availability calendar as well). I see there's a todo mentioning better handling of cancelled bookings in rooms_availability.module; is there any progress on this? I checked the dev release and the todo still exists there. I might be able to help with this if you give me a little more info about what work needs to be done.