Can't say I've seen anything substantial on this incident. Usually CASA has reports on these kinds of event events, but couldn't find anything in their Flight Safety magazine or on their website (using the search function).
Civil Aviation Safety Authority
As coincidence would have it, there was a drain mast heating problem only a few days ago on one of Qantas' 747-400's. An internal heating element failed on the Centre Drain Mast and it iced up, causing flooding in the door #4 galley and surrounding areas (well away from the Main Equipment Centre). Thankfully, there were no other side effects other than wet floors/carpets.
It was just one of those everyday events of components failing (like lightbulbs), but caused a substantial delay... despite QF Engineering's intense efforts to get the problem rectified. Engineering was most insulted to see Qantas management distrubuting a printed document amongst the inconvenienced passengers, saying the delay was due to an industrial dispute over wages! This sort of misinformation only paints management in a worse light. If it wasn't for Engineering's efforts, the aircraft, in theory, could have been delayed 24 hours (the Boeing Maintenance Manual's procedure for drain mast removal/installation calls for sealant which has a 24 hour curing time).
Rgds.
NSEU