auth.net errors

So this weekend and last weekend we have had auth.net issues and im looking to see if anyone else has had it too. (note M-F we had NO issues).

basically, we have customers that have failed orders repeatedly, but then later get a successful order.

I have it setup so that when orders fail we get a "failure email" with all their info and the failure codes. so i can see their info.

When the order does go through successfully, it seems the user isnt getting to the success page, because they are hitting the button again. this is producing a 2nd charge.

Another weird thing is.........we actually got a "failure" with the following error information:

This transaction has been approved.
Response Reason Code: 1
Address Verification Response Code: D



I feel like something is going on getting the message back from auth.net to the cart.
is anyone else having weird glitches like this?
any ideas on what i can check?
something is up but i cant figure out where to look first.

sam