Carriers disappear while doing checkout

[KimCK]

We daily have customers who can choose a carrier, but then after moving around in the checkout process is left without the option to choose a carrier.

I managed to find a repro

Repro:

Add an item to the chart

Checkout the shopping chart

Add your personal info (as a guest), click continue 

Add your address, click continue

Carriers show up. 👍

Go back to address and click edit, then continue

(you now got 2 addresses, could be the root cause, but you can still choose carrier 👍)

Click personal info, click the terms and conditions again and continue

Now the carriers are gone and you have to start over to get it working again.

Anyone seen this before, or idea what is wrong. Most customers can do a checkout successful, but we see the issue every day.

Version: 1.7.2.4

Thanks

Kim

[KimCK]

Update:

The site was very very slow, and a clean of the log table made it fast again. Since then we have not had any customer issues, however the repro above still works.

My best guess is the customers were not doing the above repro, but perhaps clicked multiple times on continue or back while the site was slow and loading.