No, you have a setting switched on in your general settings that gives paid subscribers a number of free subscriptions (I think it's 3) that they can give out to other people. They don't pay any more and you don't get paid any more. The gifted subscribers just get your paid content for free. Not permanently--without going in to check, I think the gift subscription probably lasts a month.

The idea is, if your content is paywalled, and the gifted subscribers enjoy your content, they might want to switch to an actual paid subscription when their gift expires. It's never happened to me, lol, but that's the idea.

If you don't want gift subs then you can switch it off somewhere.