Your cards fine till the end of Oct why worry about changing it before then. Just wait for the charge and shipping to go through then change it at the end.
Reading this thread reminds me of a 2007 release. I refreshed just to make sure I wasn’t timed out and they threw the add to cart button, I smoothly ordered 20 gold coins no issues. It was near 10 minutes early.
Sometimes that will happen if you refresh too much and too fast. When I buy from the mint I only refresh like once every 10 or 15 seconds. If the page hasn’t loaded by then I hit refresh and wait another 10-15 seconds and repeat. It’s worked for me so far. I actually think the most recent release of the 2021 P Morgan & Peace Dollar was the smoothest I’ve ever seen. The V75 ASE Proof and 2021 CC & O Morgan Dollar releases were a mess.
I didn't refresh at all. I only reacted when I got a message like, "URL not found", or some other message. Funny thing, I was able to get a V75 and an O Morgan. That was before the mint changed their software. At a recent coin show I traded my V75 for a proof 1874 IHC.
Sometimes when it’s super busy that order will still go through. I had one where it showed me that on the computer but I got the text message order received and then the emails and confirmations later. I’d suggest everyone use the text message feature as it can save a lot of time and hassle when the sites going crazy.