Bizarre. Carta has an opt-in liquidity program that I'd expect to be the source of this type of offer, but doesn't fit the case here.
I'm guessing someone fucked up and should not have considered this particular investor for a tender. I'm willing to give Carta the benefit of the doubt here, that this is a one-off fuck up (this type of offer being a human-managed process wouldn't surprise me as it's typically high-touch).
Because if it isn't, and it is systemic, then Carta has fired their cannons into their own hull.