Something must be going on with the reservation system. I just checked our account yesterday ( on a whim...nothing really to check for) and discovered that our remaining points were no longer fully bankable. I watch that carefully so I knew there must have been some error.
Checking closer I discovered that I now had 5 points in holding! For some reason on October 15th, our entire vacation on Oct 20 - 27 was cancelled and re-booked. An error occurred in the rebooking. I know I didn't make any changes that close to the reservation, but now I recall that when we arrived there were no room requests on our file ( now I know why)
Long story short, I called this morning....was on hold for a while as they researched it....and they fixed the problem. They have no idea how it occurred.
You shouldn't have to, but it is wise to check on-line regularly to see that your point balances are correct. Errors do occur but I have always found that MS is very quick to correct them....but....what would have happened if it was a straight cancellation without rebooking????...don't even want to think of that possibility!!!