I doubt anything will ever be proven but a very common error among those with new systems in a hurry to fly is having the mode switch in the Home/RTH position. All to frequently people will yank everything out of the box, install batteries and props to run out the door and fly it without reading any of the instructions.
I’ve come to view threads from new users where the first post initiates a rant about a product’s failure to perform as having a high probability of being caused by procedural errors that were user induced. When the OP disappears after being provided the ops info they had in their unread manual or Quick Start Guide we might view that sudden absence as embarrassment after finding out the problem was on their part, not the system’s.
People don’t like admitting when they are wrong and in all candor, full scale pilots are some of the worst in that respect. Being a pilot and associating with many over the years has only reinforced that view. The only groups worse are attorneys, doctors, and engineers.