I may try again at the new calendar year to see if it is a yearly limit or an overall limit. Anyway, when I went to redeem another one inside of Popslots it said I have met the max I can redeem with RCI. I think I have redeemed a voucher 4 times, maybe 5.
I know this thread is a bit old - but I thought I would come back and report that there must be a limit to how many times you can redeem and use on RCI.