Cart deselecting customer's shipping choice

If a customer goes to check out

Step 2: Billing - Everything is fine
Step 3: Delivery Details - There is a very long pause until it advances to Step 4. My guess is it's pulling shipping information, but it forces people to click on the continue button twice.
Step 4: Delivery Method - Choose delivery method and continue, sometimes it ends up choosing the first method of shipping which happens to be an overnight method. This happened this morning and a customer did not check their shopping cart and ended up paying for overnight shipping when all they wanted was ground.

Any ideas on what is happening and how to address the issue?

Please let the developers know about your store url. So it can be checked.

Hi,

I tested it. It worked correctly.

What might be happening is.

Say i am on step4 then step5 and now if i click step2.

So shipping option will again be set to first one. As it recalls again and gets all shipping option.

So if this was done by your client then this issue must have occurred.

Thank you for taking the time to look this over. I am aware that it does not happen every time. I noticed it happened to be the day before it happened to the customer.

I didn't go backwards, only forwards in the process. I saw the selection I chose become deselected. When I clicked on Modify for the shipping, it did in fact choose the incorrect shipping method. I chose my method again and it was correct. I've seen this months ago and again now. I can safely say, I do not believe this was a customer error, due to the fact it happened to me in testing something else in the cart.