No but they might lose Alan Jeffrey. Whom I'd happily hire if the stars aligned.
That'd be a loss for sure, yeah. I think they mainly work on Luau language stuff and developer experience / type inference? AFAIK Arseny works more on deep VM level stuff, or at least that's what he would talk about back when we were in contact.
left already
I checked his Twitter, Mastodon and blog. They all still say he works at Roblox, with no sign of having left. Where did you hear this information?