(1) The adoption relationship may not be cancelled because a necessary consent has not been obtained or is ineffective under section 1760 (2) if the prerequisites for the substitution of the consent had been met when the adoption was pronounced or if they are satisfied at the time of the decision on the application for cancellation; in this connection, there are no detrimental effects if there was no instruction or advice under section 1748 (2).
(2) The adoption relationship may not be cancelled if as a result of this the best interests of the child would be substantially endangered, unless overriding interests of the adoptive parent require the cancellation.