73. Whenever a Latin editio typica of a given liturgical book is promulgated, it is necessary that it be followed in a timely manner by the preparation of a translation of the same book, which the Conference of Bishops is to send, after having duly approved it, to the Congregation for Divine Worship and the Discipline of the Sacraments, to whom it pertains to grant the recognitio according to the norms set forth in this Instruction, and also in keeping with others established by the law.[Cf., Code of Canon Law, can. 838.] However, when it is a question of a change affecting only a part of the Latin editio typica or the insertion of new elements, these new elements are to be maintained fully and faithfully in all succeeding editions produced in the vernacular language.
… but a “timely manner” doesn’t mean quick; that would give us the interim MR1 of 1970/75. We can ask if the 17-year timeline of the English version of MR2 was a problem from Rome’ view.