I suspect what has happened is that the reservation has been changed, after which the points became "detached" from the reservation, and were then picked up by an audit.

This has happened to me twice with reservations that had been edited, although in my case, it was a double deduction after no points were returned. The IT team can generally pick these up - it seems like yours has been picked up in an audit and will be revised once someone looks at it.

As a general tip, never change an award reservation - it should work but it clearly doesn't. Always cancel and rebook.