Does Bash 5.1 block SIGINT until here-document is ready?

[Oğuz]

In Bash 5.1, Ctrl-C doesn't interrupt the command below. The only way out I
guess is to stop it Ctrl-Z and run `kill %%`, but that's really too much
work.

    cat <<!
    `sleep 10`
    !

This isn't reproducible with Bash 5.0 or Bash 4.4.

Oğuz