Incorrect child model is getting removed from BOM

Summary:

Unable to remove selected child model configuration from the parent model. It copies the configuration of the deleted child model to another existing child model.

Content (required):

We have implemented the system configuration design with Root-Parent-Children model relationship.

We are facing an issue while trying to remove any child model, it copies the configuration of the deleted child model to another child model.

Example: If I have selected and configured child-1, child-2, child-3 and then removed child-2; always the last item child-3 is removed from the back end and child-2 configuration is copied to child-3.

Is there an option to remove the child model configuration from the parent or return the child level BOM from the Parent?