Comments Plus update being attacked by bots?

Ever since updating to version 1.6.7, I've noticed several bots failing on URLs of posts that include name='comments-plus-form' appended to the URL.

What's curious is they're identifying themselves as Googlebots, but I think they're actually comment spam bots trying to attack the plugin form.

I haven't figured out how they're getting them yet, but I'm curious why these started not too long after upgrading, after I'd never seen anything similar to them in the logs before.

Any ideas, or anything I could do to slow them down? They haven't landed any spam yet, I think because the URLs they're trying don't exist...