R/e speculation.
Please - this is a rumour network.
Speculation as to accident causes has no place in an operational context.
It may lead to an investigation going astray, or operational pilots focusing on erroneous supposed causes, unnecessarily modifying SOPs and/or creating additional hazards.
But I'd suggest speculation on a forum like this is entirely appropriate - we speculate out of a passion for flight, wanting to learn and understand, and certainly not to malign a fellow pilot much more experienced than many of us who has tragically lost his life.