"Downlink data connection lost for nnn seconds"

This message shows up when the remote control got partial or no flight data from the aircraft for more than 1 second, which means the metadata downlink had issues.

It is possible that during this time there is a sense of full control of the aircraft via the remote as well as clear video, however, typically the video gets choppy and the remote controls may have some delay.

This is typically an indication that the aircraft was flying in a high interference area or that distance was a negative factor. In these conditions the aircraft is at higher risk of initiating the Return-To-Home function.