At the risk of getting labelled a spotter I would observe that with any aircraft incident:
1. The mechanical engineer thinks the cause is mechanical failure.
2. The Electrical engineer thinks the problem is electrical.
3. The radio ham thinks it's RF interference.
4. The computer programmer thinks the cause is software problems.
5. The chemist thinks it's the fuel.
.........and so on, as this thread conclusively demonstrates.
To put it another way, everyone examines things through the lens of their own experience.
The trouble is that while I'm sure the speculation is well meaning in most cases, very little of that experience has anything much to do with commercial aviation.
I'd rather wait for the experienced folk at AAIB and Boeing to tell all of us what they believe the probable cause is, because as an engineer who first was responsible for an oil terminal and airport jet fuel handling facility, then spent six years with an airline engineering division, followed by an aerospace/defence outfit, and flies little tiny aircraft, I'm buggered if I know what happened.