NTA - personally, I lived with gaslighters my whole life and only *wish* I could have recorded footage of their BS. Although I was somewhat forced into no contact with the abusive arseholes last year, shit, best thing could have ever happened to me! This strikes me as a standard melodramatic response to being caught out. It's basically "remember it my way, or sod off" logic. To me, the truth isn't the point here, it's your SO's inability to control your reality that has upset them. You obviously have an understanding of what kind of abuse has happened, as you used the term "gaslighting". The fact you even felt the need to go through the footage is something I feel so bad for you for - questioning your own reality is the early stages of what I'd call "conversion" (the last points being simply not thinking for yourself anymore). To this day I have so many stupid personality things from having been brought up essentially being told I'm mental.
The only thing I can say is have confidence in your reality and your own recollection, but be mindful of how fickle memory is. I'm sorry you've had to be exposed to this, but happy it was such a minor argument to truly expose how petty your SO is being. You're not crazy, and them trying to project their crazy onto you is just sad.
That said, I honestly think these people are confused af. If you can somehow acknowledge who your SO is, and help them through whatever this compulsion to control is, then you'd be the best thing to happen to your SO - not that it's your responsibilty, and sometimes doing what's best for your own sanity is the only answer.
So there's my essay to you (and this is the short version of my response!). Hope I've just read too much into something and taken it personally, but otherwise wish you the best in your recovery, be it with your SO, or without.