and he said that his lightsaber got destroyed by Rey
This is the first time I read about someone else noticing this, too. It happens when Rey forces Kylo’s saber into the snow, immediatly after it is deactivated you see something fly away. Really hard to make it out, but most probably, it’s his saber.
I noticed this on first viewing actually, but always forget about it. Didn’t see “something fly away,” but Rey slams down with her lightsaber right on Kylo’s hilt and there’s a sound that makes it definitely seem like his saber has been destroyed.
It’ll be interesting to see if his V2 saber will be a different. I hope not too much so, I love how the saber perfectly reflected his character (but then, I guess his character will be a bit different next time around?).