This summary is not the rule. The rule text controls.
Grandparents can sometimes still see their grandchild after an adoption, even though adoption normally cuts off ties to the birth family. This applies in two situations. First, if one of the child's parents died and the child was later adopted, that deceased parent's own mother and father (the child's grandparents) may ask for visitation. Second, if a parent lost their right to object to the adoption under the rules in Article 1245, that parent's mother and father may also ask for visitation.
This means grandparents are not automatically shut out just because an adoption happened. The law gives them a chance to request limited time with the child, even though the adoptive parents now have full legal custody. It does not guarantee visitation will happen. It only allows grandparents to seek it under these specific circumstances.
The visitation would be limited, not the same as normal parenting time. A court would still need to decide whether to grant it and how much contact makes sense for the child's well being.