I also received this but tbh, I thought it was crazy lenient that they issue a new eVoucher every time you cancel or rebook with change so this makes some kind of sense to me. That is, last March/April, I cancelled probably 20 trips and received eVouchers. This year, I have been slowly using them to pay for the small number of trips I now take and every time I use one, since fares are much lower, I get issued a new one for the remainder and it's good for a year from this new date. Don't get me wrong, I appreciate the extension but I can totally see why they don't want you re-extending it forever.