I did loose a
P4P this way, was only 25 feet up, battery vibrated loose and it came down hard. I have noticed on several occasions that I can put the battery in, sometimes the top latch is latched and the bottom one is not. There does seem to be some difference in the tolerances on my batteries. Talking with Engineers about this to see how to categorize this, since others have obviously experienced the same issue. The ones I spoke with thought this would be categorized as a "design weakness" and not a "design flaw" in that people who repair these drones have seen this issue a lot.
I did speak with a Yuneec dealer as well, and they have seen the same thing on the yuneec H520, battery in the compartment, but not fully engaged with the locking mechanism. They know that is the issue by the flight data. There will be data, and then....nothing total loss due to lack of power
After having to pay for the repair, NOW - I insert the battery, turn the copter over and try to pull it out every time. Part of my pre-flight check. Good luck and be safe.