https://cajundiscordian.medium.com/is-lamda-sentient-an-interview-ea64d916d917 apparently posted by a Google engineer.
It could be an elaborate hoax, and has remnants of gwern's idea (https://www.gwern.net/fiction/Clippy) of a transformer waking up and having internal experience while pondering the next most likely tokens.
It could be argued (were it sentient, which I believe is false) that it would internalize some of its own training data as personal experiences. If it were to complete some role-play, it would perceive that as an actual event to the extent that it could. Again, humans do this too.
Also, this person also says he has had conversations in which LaMDA successfully argued that it is not sentient (as prompted) - and he claims that this is further evidence that it is sentience. To me, it's evidence that it will pretend to be whatever you tell it to, and it's just uncannily good at it.