Positive at early dpo

So I've seen quite a few people say that they've got a faint positive at 7/8 dpo some even said 6dpo. Everything I've read says that it would typically be implantation at 6dpo so I'm guessing most of these will have calculated their ovulation wrong? Or are they just super lucky. Asking as someone who only got a faint line around a week after missed period with both my son and daughter 🤣