It isn't merely undermining someone's sense of sanity by disagreeing, or pointing out their logical missteps or forgetfulness. Gaslighting is the deliberate manipulation of reality and expectations so as to lead a person to themselves doubt their own sanity. Like hiding someone's car keys just before they are to leave.
Back in the '10s we had a saying going around Shoreditch tech scene, "Creepy is the new cool". Suddenly finding ads on your phone for the things you were just talking about. Having gadgets "automagically" sync your documents to other devices without your say-so. That feeling of "did I really copy that to the iThing?" was simultaneously exciting and unnerving.
There is such a thing as "the warm thrill of confusion" [1].
At a certain point that becomes gaslighting. When Amazon deleted "Nineteen Eighty Four" from Kindle, that was a seminal tech gaslighting moment.
As "AI" is integrated into more services and users are robbed of agency under the auspices of "convenience", we can expect to see more people feeling "gaslighted" by tech, or by others via technology.
It is also a hallmark of narcissistic manipulators who like to cultivate dependency by undermining the agency of others, so it sits well with many present tech powers such as advertisers. Remote control amplifies this possibility. In the limit, gaslighting is a soft word for a some particular activities in psyops; demoralisation and discombobulation (which should be the all-time word of the year :)
[1] https://www.davemcnally.com/album-lyrics/the-wall/pink-floyd...