Confirmed. ChatGPT is actively indexing the Fediverse, even small servers like mine who have not explicitly consented to their indexing.
So while people on Mastodon got angry about Mastodon having built-in discovery features, ChatGPT just went ahead and slurped up all your posts. 
A lot of people are missing the point.
Yes, you can opt out of ChatGPT indexing your Fediverse post. You can even do a DMCA.
But Fediverse folks believe search should be based on opt-in consent—and ChatGPT essentially just said, “Get bent!”
ChatGPT doesn’t care about your ideals.
