Shortcut R to repeat passages requires empty measures to copy to

I tried using the Repeat (copy and paste) shortcut letter R to insert a repetition I had missed in the middle of a composition. Instead of ADDING the repeated passage, the next passage after the omission was overwritten. I had to undo the copy and paste, then go to the passage after (or following) the omission and INSERT the required number of empty measures before using the R to copy and paste the repeated passage.
After this I tried to use R to repeat the last passage in the composition. It did not work. Only after creating the required number of empty measures was I able to copy and paste the final passage using the R shortcut.