Yes sad to say that Pius XII allowed this heretic (Bugnini) to sabatoge the liturgy. Even the modernist John XXIII got rid of him, but then it was too late. Some say Pius XII was very sick during this time, however his Cardinals should have put a stop to this.

Important to realize, however, that the mutilated modernist Holy Week changes were not the first measures implemented with a view toward the Novus Ordo Missae. That dubious honor goes to the dialogue Mass, which was the first preparation under Benedict XV and Pius XI.