There is a long history of the chat being kinda broken (see Cannot write in chat prompt / chat editor broken and Cannot write in chat prompt / chat editor broken 2 ). It’s been several months and this is still not fixed.
It may be MacOS-related, I’m also regularly running into Cmd + V erratically working (sometimes it does, sometimes not). Sometimes closing and reopening the Chat solves the issue, sometimes it doesn’t. Quantum programming at its best.