I don't fully understand the issue. Undo/Redo is under the Edit menu. Transpose is under the Process menu. You can select Process > Transpose as many times as you want, and transpositions will be cumulative. But you'll have to keep track of where you started if you eventually want to revert. I don't think this was any different in earlier versions, except that a long time ago some Process functions were under Edit, and Transpose may have been one of them. Is that maybe what this is about?