Perhaps the extra load on the batteries caused by the landing gear motors powering up can cause a drop in voltage on one of the components required to transmit video? Thankfully, the flight components remain unaffected. It may only happen briefly, but causes something to reinitialise, like the wifi transmitter used to broadcast the video.
Is it possible that you were manuvering the drone at the same time into a landing position (putting an extra strain on the batteries)? Might be worth trying to reproduce it, fly in a direction while lowering or raising the landing gear near the end of your flight time. If you can confirm it, then the advice would be to ensure both sticks are idling when raising or lowering the landing gear to minimise the drain on the battery. I don't usually pay special attention to it, as I haven't experienced it, but I try to fly near my landing spot after 15 to 20 mins of flying, before the warnings... I hover above the landing zone and then lower the gear (nice to watch anyway!). Then gently lower the thumbstick to land.
Does anyone have a thought on that theory? It is a toxic combination of you needing to manuver the drone to land, while needing the landing gear down, all while your battery is nearly depleated. Your flight logs may help as I'm sure they monitor voltage, stick positions. I can't remember if the landing gear position is tracked in the flight logs.