That has happened a lot to me in the last couple of years. I think the points are given to encourage you to make a points and cash booking, but the points are taken away pretty quickly if you don't use them. I only managed to use it once and got a pretty good deal. Now, I just find it annoying and unnecessary. But I think it ends up resetting the expiry date of your points each time it happens, given that it counts as an 'activity', which is possibly a good thing.