When we have the system reporting three errors with one of the circuits most likely to cause a fire (in theory, I'm not saying anything bad about Airbus) then that really is the strongest indication of the very limited information that we have to go upon. Heating circuits cause fires, on land, sea, and in the air.
If the warnings were about a failure in the galley oven (do they still have those?) most of us would nod wisely. Some of us would insist that a terrorst must have stuck a bomb in the oven...