I never used to have a problem booking award availability to/from MIA in the past in either May or November.
I have booked WTP from LHR-SFO-MIA-LHR and MFU'ed LHR-SFO no problem but the award availability for MIA-LHR is non-existent. I have looked every day since I booked these flights (the day they came out!) and no award availabilty at all.
Any idea why?