I confirm that this is a but caused by multiple clicks on address "save" button.
From what i see last version of prestashop (PS1.7.7) isn't affected, in fact after the first click the button will be disabled to avoid additional clicks.
What I'm wondering is if there's a way to "fix" the account where customer double clicked on the button, because after doing that, there's no way to have the carrier showed, also deleting all the addresses of the account, and adding new one.