Not sure if anyone else noticed, but every now and then when I place a max bid on something it forces me to pay the exact amount and DOES NOT GIVE A REFUND. (read carefully, I understand how the bidding process works)

IE. I put a max bid of 1,000,001 on an item which raises the current bid to 500k. No one else bids as the 500k stays the same all the way to the last second and doesn't change. I win the item but instead of winning it for 500k (even though it still shows 500k as current bid after it's status is "EXPIRED") and getting a 500k refund, it forces me to pay EXACTLY 1,000,001 and gives no refund. WTF?

This has happened several times with many different items. Just an hour ago the system was working properly and was giving the necessary refunds according to what the current bids were. So what changed? Why is this randomly happening? Is it a bug with the AH? If so please address it and fix it next patch please.