Hi,
Your checkout workflow is not adapted.
You put the shipping before the login and before the address.
When you log-in and when you choose an address, it can modify the shipping list and so, the shipping selection (because there is a automatic selection).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.