My understanding is that the waitlist expires at the end of the 31st day (midnight). If it doesn't match by then, it's gone. (If it would happen to match on the 30th day, the points released would go into holding. Then if the matched reservation uses less than the cancelled reservation, you would be left with the extra points in holding).
A real person has to finish up the process when a waitlist matches. So it could take a couple of days past the 31 days for the member to find out the waitlist worked.