On the checkout screen for some short period of time the customer is able to see a wrong country (if no sorting is set for the countries, then it is Afghanistan) and the field "Tax Registration ID" even if the providers default country has the setting "Tax Registration ID" required set to "Not Required".
Such behavior is currently by design, there is a feature request #PBA-61043 ("Improve checkout screen loading") to improve it.
Following workarounds can be used:
For the country it is possible to set up a highest Sort No for the default country, but keep in mind that this setting is actual for all the stores of all the resellers.
For the displayed "Tax Registration ID" field it is possible to redetermine the default style: in the layout template country.tpl set it to
display: noneif the default country does not require it:
<tr id="tr__taxRegID" style="display: none;">
and synchronize the store.