I think there is some concern about early weight bearing and I think hip dysplasia. By that I mean, forcing baby to stand and bear weight when they are very small or putting them in one of those door frame bouncers for hours a day from very early. But that's not the same thing as a baby who is moving to stand and bear weight as part of natural development. It's more forcing it before the soft tissues and joints have developed enough for it to be healthy and safe. If your LO is moving along on their own, then they're obviously ready for it, so I wouldn't let it worry you.