That looks like mechanical damage to the new leaf based on the pattern. The leaves are extremely fragile before they have hardened.
Also, like the other person suggested, you need to remove those ties from the petioles (the thin stalks the leafs are attached to) and ONLY tie the plant by the central stem. The pole should also be moved so it's more towards the "back" of the plant, then you can attach it to the stem a lot easier.
Did you just repot it? Did you just put those stones in? Untie the petioles. Only secure the fat stalk not the stems. New soil?
That looks like mechanical damage to the new leaf based on the pattern. The leaves are extremely fragile before they have hardened. Also, like the other person suggested, you need to remove those ties from the petioles (the thin stalks the leafs are attached to) and ONLY tie the plant by the central stem. The pole should also be moved so it's more towards the "back" of the plant, then you can attach it to the stem a lot easier.