I had a similar situation. When I looked at my points balance at the beginning of the week it stood at 80,000, so I was planning a weekend cat8 stay but didn't get around to finalising it. When I decided on the date I logged in yesterday to find my balance had reduced to 76,000 points because the Cheshunt Marriott had deducted 4,000 points erroneously awarded on my last stay. Ah well, I'll have to wait till my current Warsaw stay clears to make the reservation.

That's the first time this has happened in a decade of Marriott Rewards membership, 700 nights and 2 million points earned. And what's strange here is the coincidence that it happened to both me and Wickersley at the same time in 2 separate hotels an ocean apart.