I got this warning too last month, on a cool night, it was my second flight on same battery...I was told P3P was landing, no matter what I said or did. Thankfully I was not over water, and only about 500 feet away from bird...but I was at an event where ordinary citizens were milling about...I made sure it was landing away from people...and that was it, landed, no questions asked.
I checked my flight on healthydrones...it showed no adverse warnings...battery levels were good, and temp was ABOVE normal operating temps, so I was pissed that there was nothing I could pinpoint as the reason for the msg.
I chalked it up to the temperature...50F. Haven't seen that same warning since...and now that it's summer here in New York, doubt I'll see it again for a while.