A few minutes ago I was lying on my couch, busily finger-swiping through random images on the very beautiful Bing Image Feed page, when suddenly -- poof -- my TV changes channels from channel 17 (the "Fantastic Beasts and Where to Find Them" movie) to Channel 1 (a New York One station showing someone talking about politics). The two TV controllers were on my couch, but lying at least six inches away from my body, which had nothing moving but my fingers on a Samsung tablet.
I have seen TV anomalies such as this quite a few times: for example, the 3 cases reported previously here and here. I live on the 7th floor, too high for "signals from passing trucks" to be an explanation. One web site claims that your neighbor using his remote might cause your TV to change channels, but a test shows the TV remote signal does not pass through a wall. See here for many similar accounts, which sometimes create the impression of a mysterious signalling effect.
Postscript: Something very similar happened on June 21, 2019. I was lying on my couch, when suddenly the TV switches from showing "Ancient Aliens" to a blank screen with a 5 in the upper right corner (what I get if I click the 5 button on my black controller). I wasn't moving when the happened, and my foot was about 4 inches from the black controller, which was pointing perpendicular to the TV. I tried pressing "5" on that black controller from this position, and it had no effect on the TV.