Someone may be purchasing followers for your TikTok account or you may have been picked for bot accounts to follow in order to make their click farms seem more genuine.
If the bots have videos, followers, and follow people, it will be more difficult for TikTok to detect them.
This is out of your hands, but TikTok may flag your account. You can remove or block these followers, although this might not be practical as you gain more genuine followers.