I can't see much that's similar in your incident and the OP's.Very similar experience to mine today.....sudden disconnection despite the drone being fairly close.
I think that it was the first time ever that I had had this.....perhaps something in the firmware update??????
Had the wifi on the phone turned off and was in airplane mode, so I do not think that was a cause, but reading your post there are so many similarities.
It's extremely unlikely that our firmware update is at all related and the phone would not have made any difference, whether wifi and airplane mode was on or off.
There's nothing in the OP's data to suggest that the technology failed at all.Technology is great WHEN it works......