A lot of hotels put a "hold" on an extra amount (above the normal room rental rate) to cover incidentals. When they put a hold on this extra amount, they don't actually get the money - they just have reserved it in case you are close to topping out on your credit limit. Some hotels tell you this at check-in, but most don't.

If they did this, then it is typical. But if they actually charged your account and will refund part later, that sounds odd.