I have found that the IB seatmap as seen by RJ.com doesn't show whether the seats had been previously selected by other passengers. In those instances the seats didn't stick. I use Royal Air Maroc to view available seats. Then it's back to RJ to select the seats. BA immediately shows the seats selected. IB continues to show these as 'no seats'.

I also found that I couldn't select more than one seat and one flight at a time on RJ. So I had repeatedly to sign on. But it did the trick.